Papers - TERAUCHI Mamoru
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Mamoru Terauchi and Kaede Terauchi
Hirao School of Management Review 15 1 - 22 2025.3
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Mamoru Terauchi, Kaede Terauchi
Hirao School of Management Review 14 ( 1 ) 1 - 12 2024.3
Joint Work
Authorship：Lead author, Corresponding author
C. M. Christensen's perspective of the "S-Curve of Technological Development" is a cornerstone of his book "The Innovator's Dilemma." This paper examines why the "S-Curve of Technological Development" takes an "S" shape and discusses the limitations of a perspective that lacks detailed understanding of technology, using aspects that Christensen "could not see" as its subject. Next, it illustrates cases where manufacturers have succeeded by deliberately abandoning existing technologies. Finally, it points out that even if sustained innovation becomes impossible, once a technology has become indispensable to the infrastructure of modern society (even if it has become unappealing to managers and investors), it must be maintained at a minimum, and if possible, inherited in a way that "reduces the cost associated with its realization."
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Mamoru & Kaede Terauchi
Hirao School of Management Review 13 53 - 68 2023.3
Joint Work
Authorship：Lead author, Corresponding author
On January 20, 2023, as the eighth wave of COVID-19 (SARS-CoV-2 infection) in Japan has yet to subside, the Prime Minister instructed the Minister of Health, Labour and Welfare to consider changing the classification of SARS-CoV-2 infection under the Infectious Diseases Control Law. But just how much basic knowledge do Japanese citizens have about infectious diseases? As of early 2023, with over 300 deaths from SARS-CoV-2 infection being reported daily (excluding days equivalent to hospital holidays), how accurately do people recognize the knowledge of "infectious diseases" and the "immune system of the human body" that they should have learned by high school? This report presents the results of a longitudinal survey conducted among first-year university students who enrolled after the start of the COVID-19 pandemic.
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"Art" from the perspective of "communicated information" (in Japanese)
Mamoru & Kaede Terauchi
Hirao School of Management Review 13 35 - 51 2023.3
Joint Work
Authorship：Lead author, Corresponding author
Art is defined as a method of information transmission sent from a creator (sender) to a receiver, and artistic expression and artwork are information shared between the creator and the receiver. By considering the invention and evolution of the "recording media" (expression media) used in artistic expression and artwork, as well as the receivers of that artistic expression and artwork and the "cost bearers" related to it, one can understand that the changes in art and artwork from ancient Greece to the present day have been rationally carried out, regardless of whether they are in the East or the West.
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Mamoru & Kaede Terauchi
Hirao School of Management Review 13 1 - 17 2023.3
Joint Work
Authorship：Lead author, Corresponding author
The cumulative number of deaths from SARS-CoV-2 infection in Japan as of 2022 exceeded 39,000, and as of January 15, 2023, it is over 2,900 per week, with no peak in sight (the same applies to the increase in newly confirmed infections). Considering that one year consists of 52 weeks, this means that there is a possibility that more than 100,000 lives will be lost to SARS-CoV-2 infection in 2023. However, such reports are completely absent. Despite the fact that the effectiveness of vaccinations is known to wane over time, the rate of additional vaccinations is stagnant. As we approach the third "end-of-year and New Year's period without movement restrictions," we predict what it will bring (as of the end of January 2023).
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Science Guild - A consideration of the divided status of human knowledge - (in Japanese)
Mamoru Terauchi, Kaede Terauchi
Hirao School of Management Review 12 1 - 19 2022.3
Authorship：Lead author, Corresponding author
The COVID-19 pandemic, caused by SARS-CoV-2 infection, inadvertently exposed various "distortions" in modern society that existed prior to it. Among these "distortions," one notable issue is the extreme "reliance on experts," where many of us citizens have abandoned the ability to "think and act for ourselves," leading to continued confusion even two years after the pandemic declaration. Unless each individual can systematically integrate the "knowledge" that humanity possesses and act based on it, the reliance on experts will not be resolved. The current situation indicates a return to a pre-French Revolution feudal system regarding "knowledge." Now more than ever, the "sharing of knowledge" advocated by the Encyclopédistes is needed.
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What we must know now about COVID-19 (SARS-CoV-2 pandemic) (in Japanese)
Mamoru Terauchi, Kaede Terauchi
Hirao School of Management Review 11 101 - 122 2021.3
Joint Work
Authorship：Lead author, Corresponding author Publisher：Hirao School of Management, Konan University
The pandemic of SARS-CoV-2 infection (COVID-19 pandemic) confirmed in Wuhan, China, at the end of 2019 has, as of January 2021, been on a steady increase in both cumulative number of infections and cumulative deaths worldwide. While Japan has a relatively lower number of infections and deaths compared to other countries when adjusted for population, the inability to control the number of new infections due to "measures not based on scientific knowledge and scientific methods" has led to the issuance of a second state of emergency declaration for 11 prefectures. Returning to the "basics of infectious disease control" based on "scientific knowledge and scientific methods" is the only way to bring the COVID-19 pandemic under control.
DOI： 10.14990/00003802
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Preferences for STEM Subjects and Daily Life Habits among University Freshmen in Japan Reviewed International journal
K.Terauchi, G.Mizugaki, M.Terauchi, S.Yoshida
Proceedings of 2016 AAAS (American Association of the Advancement in Science) Annual Meeting 2016.2
Joint Work
Publisher：American Association of the Advancement in Science
Fifteen-year-old Japanese students ranked fourth on the 2012 Programme for International Student Assessment (PISA), part of the Organisation for Economic Co-operation and Development (OECD). In general, Japanese students are believed to have advanced math and science skills among the 65 member countries of the OECD. Nevertheless, out of the 617,500 freshmen joining all of Japan’s universities and colleges in 2015, only 151,000 will major in science, technology, engineering and math (STEM) fields during their undergraduate careers. A recent survey on public attitudes about S&T showed that only one fifth of Japanese adults are “very interested” in new scientific discoveries, whereas more than a third of US and UK residents reported being “very interested.” Why do only a quarter of Japanese students choose STEM-related subjects? At what stages in the Japanese education system do they begin to lose interest in STEM? The authors distributed a questionnaire to more than 1,700 freshmen. Out of the participants, 840 attended the two national women’s universities, 230 studied at a national university of education (which trains teachers to work in elementary, junior high, and high schools), 450 were STEM students at a private university, and 190 belonged to one of the non-STEM departments at another private university. By applying k-means clustering, the authors categorized the students based on their responses to questions about daily life habits. For all students in each cluster, the authors analyzed the subjects that students liked and disliked in elementary school, junior high, and high school, as well as their strong and weak subjects. The authors found that regardless of the students’ various characteristics (e.g. male or female, STEM or non-STEM majors), they were able to classify all the participants into nine clusters according to their tendencies towards “sociability” (S), “interest in nature/living creatures” (N), and “interest in machinery/manufacturing” (M). Two of these clusters (S+N+M- and S+N-M-) represent students who selected non-STEM majors and dislike mathematics and science. Four (S+N+M+, S+N-M-, S-N-M+, and S-N-M-) represent students who chose STEM majors and do not dislike mathematics, and three (S+N+M+, S-N+M+, and S-N-M-) are composed of those who earned relatively high grades in both STEM and non-STEM subjects in high school. The most noticeable result is that in all clusters, the percentage of students who began to recognize mathematics/science as their weak subject(s) drastically increased as they entered high school. The authors even observed this tendency in the groups where students chose STEM majors. These findings imply some kind of barrier in Japan’s mathematics and science curricula, most notably in the transition from junior high to high school. The authors are trying to describe these barriers in detail and determine effective solutions.
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A Consideration of Energy Resources Consumed in Japan (in Japanese) Reviewed
Mamoru Terauchi and Kaede Terauchi
Journal of Energy and Environmental Education 10 ( 1 ) 45 - 54 2016.1
Joint Work
Authorship：Lead author, Corresponding author
Currently, Japan relies on imports for more than 90% of its energy resources. To support the abundant and convenient daily life powered by electricity, more than 20% of the total energy resources supplied domestically are expended as "losses" during the energy resource form conversion process known as "power generation." This situation has not fundamentally changed since the Great East Japan Earthquake and the subsequent accident at the Fukushima Daiichi Nuclear Power Plant in 2011, and the loss ratio has actually increased. The per capita energy resource supply in 2013 was more than 36 times that of 1880. Compared to 1990, while the energy resource consumption in 2013 remained almost unchanged, the energy resource supply increased by more than 6%. This increase corresponds to the rise in conversion losses due to the reactivation of old, inefficient thermal power plants. Additionally, the energy consumption in the industrial sector in 2013 decreased by more than 8% compared to 1990, while the energy consumption in the residential and transportation sectors increased by more than 15% and 6%, respectively. This reflects the increased electricity usage due to the proliferation of information and communication devices in the residential sector and the increased energy consumption from passenger cars in the transportation sector. The latter is supported by the fact that the number of passenger cars in 2013 was 1.71 times that of 1990.
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On the technology literacy education (including information technology) (in Japanese)
Mamoru Terauchi and Kaede Terauchi
Hirao School of Management Review 5 17 - 24 2015.3
Joint Work
Authorship：Lead author
In Japanese, the concepts of "technology" and "science" are often used interchangeably in daily life without explicit definitions, but they should originally be clearly distinguished. However, their cutting edges are "science-based technology" and "technology-based science," and today they are in an interdependent relationship. Nevertheless, even in the cutting-edge ICT (information communication technology), the essence of technology, which is "learning from failure," has not changed at all. This is precisely what should be understood by everyone as "fundamental technological literacy" along with "information literacy."
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Mamoru Terauchi and Kaede Terauchi
Hirao School of Management Review 5 25 - 36 2015.3
Joint Work
Authorship：Lead author, Corresponding author
By examining the shifts in the relationship between "science" and "technology" at major turning points in the expansion of knowledge about the natural world—from Newton's classical mechanics at the end of the 17th century, to Maxwell's systematization of electromagnetism in the late 19th century, to the birth of quantum mechanics in the 20th century—we conclude that "science" is always developed in dependence on the "technology" of its time, and that a finite amount of time is necessarily required for new "knowledge" to benefit "technology." Additionally, we propose "quantitative predictability" as a characteristic feature of "modern science" since Newtonian mechanics, and also point out the importance of considering the "cost" of bearing "science that exceeds one human being's capabilities."
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Things to know when considering a 'Hydrogen Energy Society' (in Japanese)
Mamoru Terauchi and Kaede Terauchi
Hirao School of Management Review 5 37 - 42 2015.3
Joint Work
Authorship：Lead author, Corresponding author
Hydrogen is a substance that is almost non-existent in its pure form on Earth and requires energy obtained from other energy resources for its production. Additionally, with a boiling point of 20 K (minus 253°C), it is extremely low, and it cannot be liquefied at room temperature. Therefore, compared to fossil fuels (hydrocarbons) like gasoline and kerosene, which are liquids at room temperature, hydrogen requires more energy for transportation and storage. These fundamental properties of hydrogen must be considered when contemplating a "hydrogen energy society."
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Physics education in university 20 ( 1 ) 27 - 30 2014.3
Joint Work
Authorship：Lead author
When we actually conducted a lecture using numerical data on the trends in energy supply by resource and final energy consumption by sector in Japan during the latter half of the 2013 academic year, we were strongly made aware that the common knowledge about "energy" held by current university students is completely different from that of the author, who experienced the first oil shock as a child. It is thought that university students' common knowledge about "energy" is largely influenced by the content of "energy education" in the elementary and junior high school curriculum. This report introduces one aspect of this situation and the materials and reactions of university students who attended the lecture, which the author devised to explain the fact that "Japan is dependent on foreign countries for most of its energy resources."
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On the Quantitative Data to Utilize in Learning About "Renewable Energy" (in Japanese) Reviewed
Mamoru Terauchi and Kaede Terauchi
Physics education in university 19 ( 3 ) 96 - 100 2013.11
Joint Work
Authorship：Lead author
This paper quantitatively illustrates how much energy Japan has obtained through various means and how it has been used in different sectors, based on the "EDMC/Energy and Economic Statistics Handbook (2013 Edition)" published by the Japan Institute of Energy Economics. Next, it provides estimates based on natural scientific knowledge of how much energy can be extracted from solar, solar thermal, wind, geothermal, and other sources that we currently consider "renewable energy."
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Mamoru Terauchi and Kaede Terauchi
Study on politics and economy ( 98 ) 78 - 92 2012.6
Joint Work
Authorship：Lead author, Corresponding author
The Great East Japan Earthquake on March 11, 2011, revealed how much our current daily lives depend on the accumulation of science and technology that humanity has achieved so far, and how little we had recognized these sciences and technologies. The accident at the Fukushima Daiichi Nuclear Power Plant is forcing each of us to confront scientific and technological judgments that we have previously overlooked.
This paper describes several items that the author considers to be the minimum level of "scientific literacy" based on "scientific knowledge." In particular, it explains "how radiation protection standards are determined based on what knowledge" and "what is not known about the biological effects of radiation." -
A Consideration of "Science" and "Literacy" (in Japanese) Reviewed
Mamoru Terauchi and Kaede Terauchi
Study on politics and economy ( 93 ) 71 - 78 2009.11
Joint Work
Authorship：Lead author
The terms "science" and "literacy" are used in Japan to convey meanings that are somewhat different from their Western connotations. This paper re-examines the definitions of these terms from their etymological origins and proposes more appropriate Japanese expressions for the concepts they originally represent. It questions the essence of "learning" and emphasizes the importance of "cultivation."
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Kaede Terauchi and Mamoru Terauchi
Journal of science education in Japan 32 ( 3 ) 236 - 237 2008.9
Joint Work
The fact that four Japanese researchers were awarded the 2008 Nobel Prizes in Physics and Chemistry drew attention to basic scientific research. However, it is crucial to note that all four doctors received an elementary and secondary education that was free from the division between the humanities and sciences, prior to the "yutori education" curriculum. This underscores the urgent need to promptly address and correct the trend towards specialization.
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U.S. IT Hegemony (in Japanese) Reviewed
Mamoru Terauchi
Study on politics and economy ( 78 ) 89 - 99 2002.5
Single Work
Authorship：Lead author
When examining U.S. IT hegemony from two specific perspectives—cryptography-related technology export controls and Microsoft's OS strategy—it becomes clear that the U.S. federal government plays a powerful guiding role in the conquest of the "new continent" of network society. What we should do now is not be swayed by the forced use of IT that has been de facto standardized by the U.S., but rather sincerely learn why the U.S. was able to achieve IT hegemony.
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Mamoru Terauchi
Study on politics and economy ( 76 ) 67 - 78 2001.3
Single Work
Authorship：Lead author
Even within the Linux Community, which symbolizes a completely different stance from the traditional capital-based "information enclosure" strategy, a "global conquest" is steadily advancing through the same business model as that employed by "new monopolistic capital" from companies like Microsoft. The choice between actively engaging in the "general and scientific labor" of network society or merely participating in "transformed physical labor" depends on each individual's "independent intellectual growth."
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PC bubble - market strategies of Intel and Microsoft - (in Japanese) Reviewed
Mamoru Terauchi
Study on politics and economy ( 74 ) 71 - 80 2000.3
Single Work
Authorship：Lead author
Today, the market strategies of Intel and Microsoft, which are seen as symbols of the prosperity of the U.S. information-related industries, share a clear common approach: the realization of "thorough backward compatibility plus α." Additionally, their strategies of 1) popularization, 2) monopolization, and 3) bringing competition into their own areas of expertise are also common. Both companies have actively sought to capture end-users through concept proposals related to final products. In contrast, Japan's semiconductor industry, which cannot clearly present the concept of the final product in which its products are used to end-users, has been in long-term decline. However, the current situation of Intel and Microsoft shows that concept proposals with thin user benefits are becoming more apparent, and the collapse of the PC bubble may be near.
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Software-driven dominance of DRAM market - A consideration of DRAM price trends - (in Japanese) Reviewed
Mamoru Terauchi
Study on politics and economy ( 73 ) 73 - 80 1999.11
Single Work
Authorship：Lead author
The supply and demand for Dynamic Random Access Memory (DRAM) are determined by the number of DRAM modules installed in personal computers (PCs). With the spread of 32-bit PCs, the main memory capacity of PCs has come to be determined by software such as applications and operating systems. In recent years, the main memory capacity of PCs has steadily increased (doubling every three years) in line with changes in Microsoft's Windows series. However, because the speed of DRAM high integration (quadrupling every three years), which followed past trends, was faster, it resulted in a significant price drop. Unless DRAM manufacturers can present new uses for DRAM to end-users more clearly than before, the dependence on software manufacturers for increased DRAM usage will continue, and it will be difficult to achieve independent improvement in the profitability of the DRAM business.
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A Test Circuit for Evaluating Characteristics Mismatch in Metal-Oxide- Semiconductor Field- Effect Transistor Pairs by Estimating Conductance Variation through Voltage Measurement Reviewed
Mamoru Terauchi, Kazuo Terada
Japanese Journal of Applied Physics 47 4480 - 4486 2008.6
Joint Work
Authorship：Lead author, Corresponding author
A procedure is described for evaluating characteristics mismatch in a pair of metal–oxide–semiconductor field-effect transistors (MOSFETs), which are nominally designed to be identical. This procedure is based on conductance variation estimation through voltage measurement. By measuring the gate voltage dependence of the voltage of the middle point of a MOSFET pair connected in series, various pieces of information on difference in characteristics (e.g., channel width difference and threshold voltage difference) in the MOSFET pair can be extracted. The applicability of the proposed procedure to fabrication process monitoring is also described and the principle of a suitable test circuit structure is illustrated.
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Impact of Substrate Bias on Fixed-Pattern- Noise in Active Pixel Sensor Cells Reviewed
Mamoru Terauchi
Japanese Journal of Applied Physics 46 7303 - 7305 2007.11
Single Work
Authorship：Lead author
The study investigated the impact of substrate (body) bias on fixed pattern noise (FPN) in Active Pixel Sensors (APS). By measuring a test device that serially connects two metal-oxide-semiconductor field-effect transistors (MOSFETs) placed within the same well region, it was revealed that the finite substrate bias, which is inevitable in conventional APS cell circuits using traditional methods, degrades the characteristic fluctuations of the source follower amplifier included in the APS cell. This results in FPN that cannot be improved by conventional correction methods such as correlated double sampling. Furthermore, it was shown that the current-voltage characteristics of the logarithmic conversion circuit, achieved by connecting the gate and drain of the MOSFET, are also affected by the substrate bias, leading to increased characteristic variations compared to when the substrate bias is zero.
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Feasibility Study of a Novel Four Transistor Silicon-on-Insulator Static Random Access Memory Cell Utilizing Partial Trench Isolation Reviewed
Mamoru Terauchi
Japanese Journal of Applied Physics 46 5136 - 5138 2007.8
Single Work
Authorship：Lead author
A new static random access memory (SRAM) is proposed, consisting of four thin-film SOI (Silicon-On-Insulator) metal-oxide-semiconductor field-effect transistors (MOSFETs) fabricated on a thin-film SOI substrate with a target operating voltage of 0.5 V. In this new SRAM, the body regions of the oppositely connected transistor pairs are utilized as load resistors. The transfer MOSFETs connecting each SRAM cell to the word line are dynamic threshold MOSFETs (DTMOS). By employing a partial trench isolation method, the special gate electrode shape required for body contact realization is eliminated in the SRAM cells of this study. Using a device simulator with circuit analysis functionality, it was confirmed that the proposed SRAM cell operates normally at the low voltage of 0.5 V.
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Impact of Forward Substrate Bias on Threshold Voltage Fluctuation in Metal- Oxide-Semiconductor Field-Effect Transistors Reviewed
Mamoru Terauchi
Japanese Journal of Applied Physics 46 4105 - 4107 2007.7
Single Work
Authorship：Lead author
The impact of forward body (substrate) bias voltage on the threshold voltage (Vth) of metal-oxide-semiconductor field-effect transistors (MOSFETs) and its dependence on device parameters (such as gate length, substrate impurity concentration, and gate oxide thickness) were investigated using a charge-sharing model. It was shown that applying a forward body bias voltage of 0.5 V can suppress Vth fluctuations by up to 20% in devices with a gate length of 100 nm or less, and reduce the sensitivity of Vth to device parameters. Additionally, experimental results demonstrating the Vth fluctuation suppression effect due to forward body bias voltage were presented.
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A Wide-Dynamic Range Photodiode-Type Active Pixel Sensor Cell with Seamlessly Combined Logarithmic-Linear- Logarithmic Response Reviewed
Atsushi Hamasaki, Mamoru Terauchi, Kenju Horii
Japanese Journal of Applied Physics 46 4051 - 4054 2007.7
Joint Work
A photodiode (PD) type active pixel sensor (APS) cell with a continuous log-linear-log response over a wide dynamic range is proposed for the first time, and its operation is confirmed through circuit simulation. The proposed APS cell has two additional MOSFETs connected in parallel to the reset MOSFET (metal-oxide-semiconductor field-effect transistor) compared to the conventional 3-transistor (3Tr) type PD APS cell. By utilizing the previously proposed operating method, it is shown that the newly proposed 5Tr type PD APS cell exhibits a continuous log-linear-log response.
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Temperature Dependence of the Subthreshold Characteristics of Dynamic Threshold Metal-Oxide- Semiconductor Field-Effect Transistors and Its Application to an Absolute-Temperature Sensing Scheme for Low-Voltage Operation Reviewed
Mamoru Terauchi
Japanese Journal of Applied Physics 46 4102 - 4104 2007.7
Single Work
Authorship：Lead author
A method for detecting absolute temperature based on the temperature dependence of the voltage-current characteristics of dynamic threshold metal-oxide-semiconductor field-effect transistors (DTMOS) in the subthreshold region is proposed. This proposed method does not require voltages greater than 0.5 V or initial calibration. While this method is well-suited for SOI (Silicon-On-Insulator) circuits based on SOI technology using SOI substrates, it can also be easily applied to conventional bulk MOS devices. Experimental results of absolute temperature measurement using bulk MOS devices are also presented.
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Hamasaki, Terauchi, Horii
The journal of the Institute of Image Information and Television Engineers 60 ( 7 ) 1111 - 1113 2006.7
Joint Work
A novel operation scheme that creates combined linear-logarithmic responses in photodiode (PD)-type 4-transistors active pixel sensor (APS) cells is described. we found that our APS cells can be operated with seamlessly combined linear-logarithmic responses by setting the reset transistor in weak inversion through properly selected bias voltages.
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A Novel Operation Scheme for Realizing Combined Linear- Logarithmic Response in Photodiode-Type Active Pixel Sensor Cells Reviewed
Atsushi Hamasaki, Mamoru Terauchi, Kenju Horii
Japanese Journal of Applied Physics 45 3326 - 3329 2006.4
Joint Work
We propose a photodiode (PD) type active pixel sensor (APS) cell with a continuous linear-logarithmic response. In a 3-transistor (3Tr) type PD APS cell, by appropriately selecting the bias voltage to operate the reset transistor in the weak inversion region, we have shown through simulation that the conventional 3Tr PD APS cell exhibits a continuous linear-logarithmic response. We also discuss methods to expand the dynamic range in the linear response region of conventional APS cells
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A Novel Operation Scheme for Realizing Combined Linear- Logarithmic Response in Photodiode- Type Active Pixel Sensor Cells Reviewed
Atsushi Hamasaki, Mamoru Terauchi, Kenju Horii
Extended Abstracts of the 2005 International Conference on Solid-State Devices and Materials 666 - 667 2005.9
Joint Work
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Selectable Logarithmic/Linear Response Active Pixel Sensor Cell with Reduced Fixed-Pattern- Noise Based on Dynamic Threshold MOS Operation Reviewed
Mamoru Terauchi, Atsushi Hamasaki, Arinori Suketa
Japanese Journal of Applied Physics 44 2347 - 2350 2005.4
Joint Work
Authorship：Lead author
A new active pixel sensor (APS) cell is proposed that has lower fixed pattern noise (FPN) compared to conventional devices and can select between linear and logarithmic responses. This APS cell consists of four dynamic threshold metal-oxide-semiconductor field-effect transistors (DTMOS). DTMOS inherently has smaller characteristic fluctuations compared to conventional MOSFETs, which can be explained by the charge-sharing model. Therefore, the proposed APS cell exhibits lower FPN in the logarithmic response region compared to conventional logarithmic response APS cells, even without an external noise reduction circuit. The FPN reduction achieved by the proposed APS cell was confirmed by measuring a test circuit that mimics the readout circuit of a real device.
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A Selectable Logarithmic / Linear Response Active Pixel Sensor Cell with Reduced Fixed-Pattern- Noise Based on DTMOS Operation Reviewed
Mamoru Terauchi, Atsushi Hamasaki, Arinori Suketa
Extended Abstracts of the 2004 International Conference on Solid-State Devices and Materials 504 - 505 2004.9
Joint Work
Authorship：Lead author
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SOI SRAM / DRAM Cells for 0.5 V Operation Reviewed
Mamoru Terauchi
Japanese Journal of Applied Physics 43 2160 - 2165 2004.4
Single Work
Authorship：Lead author
Described are a 4-transistor static random access memory (4T SRAM) and a dynamic random access memory (DRAM) gain cell, both created using SOI (Silicon-On-Insulator) substrates and capable of low-voltage operation. Both cells actively utilize the body regions of partially depleted SOI metal-oxide-semiconductor field-effect transistors (MOSFETs). In the 4T SRAM cell, the body region of an SOI MOSFET with an H-shaped gate electrode is used as the load resistor for the proposed SRAM cell's inverter pair, and its resistance value can be controlled independently of the MOSFET's threshold voltage. Simulation results demonstrated the stable operation of the proposed 4T SRAM at a power supply voltage of 0.5 V. The SOI DRAM gain cell consists of a p-channel junction field-effect transistor (JFET) and an n-channel MOSFET, with the MOSFET's source diffusion layer also serving as the JFET's gate diffusion layer. The signal charge is stored in the gate junction capacitance of this JFET, modulating its source-drain conductance. Simulation results confirmed that the proposed SOI DRAM gain cell operates normally at a power supply voltage of 0.5 V.
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A Novel Photodiode- Type Active Pixel Sensor Utilizing DTMOS with Reduced Fixed-Pattern Noise Reviewed
Technical Digest of 2003 IEEE International SOI Conference 57 - 58 2003.10
Single Work
Authorship：Lead author
A novel active pixel sensor with reduced fixed-pattern-noise is proposed and its effectiveness is experimentally verified. Smaller characteristics fluctuation in threshold voltage and drain conductance of DTMOS than that of bulk counterpart considerably reduces fixed-pattern-noise of the proposed photodiode-type APS.
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SOI SRAM / DRAM Cells for 0.5 Volt Operation Reviewed
Mamoru Terauchi
Extended Abstracts of the 2003 International Conference on Solid-State Devices and Materials 620 - 621 2003.9
Single Work
Authorship：Lead author
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A 'Self-Body- Biased' SOI MOSFET: A Novel Body-Voltage- Controlled SOI MOSFET for Low Voltage Applications Reviewed
Mamoru Terauchi, Shichio Funakoshi
Japanese Journal of Applied Physics 42 2014 - 2019 2003.4
Joint Work
Authorship：Lead author
A new body potential control scheme for SOI (Silicon-On-Insulator) metal-oxide-semiconductor field-effect transistors (MOSFETs) is proposed, and its characteristics are investigated through simulation. In the "on" state, the body potential is electrically isolated from the external body terminal by the gate depletion layer and is automatically controlled by the drain voltage and drain current. This new structure is predicted by simulation to achieve over 30% increase in current drive capability compared to an equivalent MOSFET using a bulk substrate. Mixed-mode simulation revealed that a CMOS inverter composed of the proposed device has a shorter propagation delay compared to a bulk CMOS inverter. Furthermore, simulation showed that the proposed device does not exhibit the history effect on propagation delay that is characteristic of conventional partially depleted SOI devices. This is because, in the "off" state, the proposed device is equivalent to a conventional body-tied partially depleted SOI device, allowing excess majority carriers, the main cause of the history effect, to be swept out from the body terminal each time the device turns off.
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A Logic-Process- Compatible SOI DRAM Gain Cell Operating at 0.5 Volt Reviewed
Mamoru Terauchi
Technical Digest of 2002 IEEE International SOI Conference 86 - 87 2002.10
Single Work
Authorship：Lead author
A novel SOI DRAM gain cell operating at 0.5 V is proposed. It consists of a p-channel JFET and an n-channel MOSFET, whose source diffusion functions as gate diffusion of the JFET as well. Signal charge is stored in the gate diffusion capacitance of the JFET, leading to the modulation in its source-drain conductance. Mixed-mode simulation with the use of a device simulator reveals that the proposed SOI DRAM gain cell is able to operate properly under supply voltage as low as 0.5 V.
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'History Effect'- Free Operation of 'SBB' SOI MOSFETs Reviewed
Mamoru Terauchi, Shichio Funakoshi
Extended Abstract of 2002 International Conference on Solid-State Devices and Materials 596 - 597 2002.9
Joint Work
Authorship：Lead author
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Threshold Voltage Fluctuation Analysis in Dynamic Threshold MOSFET Based on Charge-Sharing Reviewed
Mamoru Terauchi
Technical Digest of 2001 IEEE International SOI Conference 53 - 54 2001.10
Single Work
Authorship：Lead author
Threshold voltage (V/sub th/) fluctuation in Dynamic Threshold MOSFET (DTMOS) is analyzed based on a charge-sharing model. It has been revealed that the gate depiction layer width in DTMOS devices is smaller than that in body-tied partially-depleted SOI MOSFETs (PDSOI) or bulk MOSFET in normal conditions, leading to smaller V/sub th/ fluctuation in DTMOS (/spl sigma//sub Vth//sup DT/) due to impurity number fluctuation in the gate depiction layer. Vth sensitivity on both impurity concentration (N/sub a/) and gate oxide thickness (T/sub ox/) is also reduced in DTMOS.
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A Novel 4T SRAM Cell Utilizing 'Self-Body- Biased' SOI MOSFET Structure Operating at 0.5 Volt Reviewed
Mamoru Terauchi
Technical Digest of 2000 IEEE International SOI Conference 108 - 109 2000.10
Single Work
Authorship：Lead author
A novel 4T SRAM cell utilizing the 'self-body-biased' ('SBB') SOI MOSFET structure (Terauchi and Terada, Proc. IEEE Int. SOI Conf., p. 36, 1999) is proposed. The body region of an SOI MOSFET with an 'H-shaped' gate electrode is used as a resistor in the inverter pair of the SRAM cell. The resistance of the body region is controlled by the low impurity concentration region beneath the auxiliary gate electrode and its geometry, independently from the threshold voltage of the MOSFET. Device simulation reveals the stable operation of the proposed SRAM cell under supply voltage of as low as 0.5 V.
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Design Guideline and Performance Prediction of 'SBB' SOI MOSFETs Reviewed
Shichio Funakoshi, Mamoru Terauchi
Technical Digest of 2000 IEEE International SOI Conference 52 - 53 2000.10
Joint Work
Characteristics of 'self-body-biased' ('SBB') SOI MOSFETs (Terauchi and Terada, 1999) have been studied in detail. Static simulations show that both the desired off-state leakage current (I/sub off/) and the on-state current (I/sub on/) ratio (I/sub on//I/sub off/) can be achieved by independently changing the impurity concentration of the 'high Na' and the 'low Na' regions of 'SBB' SOI MOSFETs. Transient simulations reveal that an inverter made of 'SBB' CMOS devices has up to 30% shorter propagation delay (/spl tau//sub pd/) at a supply voltage of 0.9 V than that for a bulk CMOS inverter under a relatively heavy load condition (load capacitance of 1 pF).
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'Self-Body- Biased' SOI MOSFET through 'Depletion Isolation Effect' Reviewed
Mamoru Terauchi, Kazuo Terada
Technical Digest of 1999 International SOI Conference 36 - 37 1999.10
Joint Work
Authorship：Lead author, Corresponding author
A new SOI MOSFET structure utilizing a novel body potential control scheme is proposed. In its 'on' state, its body potential is electrically isolated from the external body terminal by the gate depletion layer, and is controlled automatically through the drain current and drain voltage. More than 30% improvement in current drivability is predicted.
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The Effect of Ion Implantation on the Gate Oxide Integrity of SOI Wafers Reviewed
Terauchi, Samata, Kubota, Yoshimi
Technical Digest of 1998 International SOI Conference 125 - 126 1998.10
Joint Work
Authorship：Lead author
The effect of ion implantation on the gate oxide integrity (GOI) of SOI wafers has been investigated. It has been found that the GOI of SOI wafers is significantly affected by ion implantation to the SOI layer before gate oxidation. SOI wafers are found to be more sensitive to metal contamination than bulk wafers because the buried oxide (BOX) layer functions as a diffusion barrier for metal contamination. The effect of the SOI-BOX interface on the gettering of metal contamination is also discussed.
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Evaluation of 0.3 micron Poly-Silicon CMOS Circuits for Intelligent Power IC Application Reviewed
Tomoko Matsudai, Mamoru Terauchi, Makoto Yoshimi, Norio Yasuhara, Yukihiro Ushiku, Akio Nakagawa
Japanese Journal of Applied Physics 37 1103 - 1106 1998.4
Joint Work
In this paper, we report on the fine device performance of a 0.3 μm gate length polysilicon complementary metal-oxide-semiconductor (CMOS). The breakdown voltage of 0.3 μm n-channel metal-oxide-semiconductor field effect transistor (NMOSFET) devices exceeds 6 V, which is higher than that of NMOSFET devices on separation by implanted oxygen (SIMOX) wafer. The drain current of a 10 μm channel width device is 540 μA, which is one-fifth of that of NMOSFET on SIMOX. The leakage current is less than 10-11 AJ/μm, when the gate voltage is below O V. The S-factor is 125 mV/dec, and the threshold voltage is 0.4 V. Therefore the ON/OFF current ratio is greater than 10^7 . A delay time of 1 ns is achieved in polysilicon NAND rings. Hence, it is ascertained that the polysilicon CMOS is applicable for the fabrication of control and protection circuits on
power devices. -
'Depletion Isolation Effect' of Surrounding Gate Transistors Reviewed
Mamoru Terauchi, Akihiro Nitayama, Naoyuki Shigyo, Fumio Horiguchi
IEEE Transactions on Electron Devices 44 2303 - 2305 1997.12
Joint Work
Authorship：Lead author
A surround gate type metal-oxide-semiconductor field-effect transistor (SGT) with a size of 0.5 microns or less was created, and its voltage-current characteristics were studied. Even in an SGT where the silicon pillar is not completely depleted (for example, a 0.6-micron SGT), ideal voltage-current characteristics unique to fully depleted SOI (Silicon-On-Insulator) devices (such as a subthreshold coefficient close to 60 mV/dec at room temperature and a threshold voltage independent of the substrate bias voltage) were observed by using the lower diffusion layer of the silicon pillar as the drain and applying a sufficiently high voltage (depletion isolation effect).
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Advantage of SOI Technology in Low Voltage ULSIs Reviewed
M. Yoshimi, S. Kawanaka, T. Yamada, M. Terauchi, T. Shino, T. Fuse, Y. Oowaki, S. Watanabe
SPIE Microelectronic Device Technology 3212 178 - 187 1997.10
Joint Work
Low power advantage of SOI (silicon-on-insulator) technology is presented. A 0.5 V operation ALU is demonstrated by employing a gate-to-body connected structure. From the viewpoint of reliability in process integration, origin of a leakage current between source and drain is investigated in detail. The performance advantage of fabricated SOI ALUs over bulk devices as well as issues to be overcome are discussed.
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An Ultra Low Voltage SOI CMOS Pass-Gate Logic Reviewed
Fuse, Oowaki, Terauchi, Watanabe, Yoshimi, Oouchi, Matsunaga
IEICE Transactions on Electronics E80-C 472 - 477 1997.10
Joint Work
An ultra low voltage CMOS pass-gate logic using body-bias controlled SOI MOSFETs has been developed. The logic is composed of gate-body connected SOI pass-gates and a CMOS buffer with the body-bias controlled by the complementary double-rail input. The full-adder using the proposed logic improved the lowest operation voltage by 27%, compared with the SOI CPL (Complementary Pass-Gate Logic). For a 16 16 bit multiplier, the power-delay product achieved 70 pJ (including 50 pF I/O) at 0.5 V power supply, which was more than 1 order of magnitude improvement over the bulk CPL.
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Evaluation of 0.3 micron Poly-Silicon CMOS Circuits for Intelligent Power IC Application Reviewed
Tomoko Matsudai, Mamoru Terauchi, Makoto Yoshimi, Norio Yasuhara, Yukihiro Ushiku, Akio Nakagawa
Extended Abstracts of the 1997 International Conference on Solid-State Devices and Materials 378 - 379 1997.9
Joint Work
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Yoshimi, Terauchi, Nishiyama, Arisumi, Matsuzawa, Shigyo, Takeno, Tomita, Suzuki, Ushiku, Tango
IEEE Transactions on Electron Devices 44 423 - 430 1997.3
Joint Work
The bandgap engineering method using a SiGe source structure is presented as a means to suppress the floating-body effect in SOI MOSFET's. Experiments using Ge implantation are carried out to form a narrow-bandgapped SiGe layer in the source region. It has been confirmed that Ge-implanted SIMOX exhibited a 0.1 eV bandgap narrowing with a relatively low Ge-dosage of 10/sup 16/ cm/sup -2/. The fabricated N-type SOI-MOSFET's exhibited suppressed parasitic bipolar effects, such as improvement of the drain breakdown voltage or latch voltage, and suppression of abnormal subthreshold slope. Advantages over other conventional methods are also discussed, indicating that the bandgap engineering provides a practical method to suppress the floating-body effect.
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A 0.5V 200Mhz 1-stage 32b ALU using a body bias controlled SOI Pass-Gate Logic Reviewed
Fuse, Oowaki, Yamada, Kamoshida, Oota, Shino, Kawanaka, Terauchi, Yoshida, Matsubara, et al.
Technical Digest of 1997 IEEE International Solid-State Circuits Conference 286 - 287 1997.2
Joint Work
SOI CMOS with gate-body connection (DTMOS) and body bias controlled SOI pass-gate logic (BCSOI pass-gate) take advantage of individually isolated SOI device active area and reduce threshold voltage by controlling each device body bias. Hence, they enjoy higher speed than circuits based on fixed low threshold voltage. The direct body bias control used in previous work suffers from leakage current at supply voltage higher than 0.8V due to drain-body junction leakage. A practical circuit technology that offers the highest speed, lowest operation voltage and stable operation under wide supply voltage demonstrates performance with an ALU macro using this technology.
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The Impact of the Floating-Body Effect Suppression on SOI Integrated Circuits Reviewed
Mamoru Terauchi, Akira Nishiyama, Tomohisa Mizuno, Makoto Yoshimi, Shigeyoshi Watanabe
Technical Digest of 1996 IEEE International Electron Devices Meeting 855 - 858 1996.12
Joint Work
Authorship：Lead author
The bandgap engineering technique suppresses not only anomalies in the DC transfer characteristics of SOI CMOS circuits but also characteristics fluctuations of SOI MOSFETs. It is experimentally verified that the floating-body effects in 8 k SOI MOSFETs in 0.7 mm/sup 2/ wafer area cannot be controlled completely with a conventional fabrication technique. Thus it is concluded that the suppression of the floating body effects is essential to fabricate actual LSIs utilizing SOI devices.
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Analysis of Floating-Body-Induced Leakage Current in 0.15 micron SOI DRAM Reviewed
Mamoru Terauchi, Makoto Yoshimi
Technical Digest of 1996 IEEE International SOI Conference 138 - 139 1996.10
Joint Work
Authorship：Lead author
Summary form only given. Degradation of the dynamic retention time in SOI DRAMs is a critical issue in the application of SOI technology to memory devices. One possible degradation mode related with the floating-body effect occurs in a non-selected memory cell storing "1" due to a transient lowering of the threshold voltage (Vth) of the transistor associated with a voltage drop of a data line from a precharge level to 0 V. It was reported that this dynamism can induce a leakage current as high as several mA at low voltage regions. In this paper, the possibility of this degradation mode in a 0.15 /spl mu/m SOI DRAM cell is analyzed in detail considering various device parameters and the design guideline to avoid the degradation is described.
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Reduction of the Floating-Body Effect in SOI-MOSFETs by the Bandgap Engineering Method Reviewed
Yoshimi, NIshiyama, Arisumi, Terauchi, Matsuzawa, Shigyo
Proceedings of 7th International Symposium on Silicon-On-Insulator Technology and Devices 231 - 236 1996.10
Joint Work
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Advantages of Low Voltage Applications and Issues to be Solved in SOI Technology Reviewed
Yoshimi, Terauchi, Nishiyama, Numano, Kubota, Watanabe, Tango
Technical Digest of 1996 IEEE International SOI Conference 4 - 5 1996.10
Joint Work
With low voltage applications as the main objective, SOI technology has made rapid and substantial progress in recent years. This paper describes the current status of SOI technology with emphasis on analysis of dynamic retention characteristics in low voltage DRAMs, countermeasures regarding the floating-body effect in low voltage region, and reliability issues in state-of-the-art SOI substrate technology.
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Analysis of Si-Ge Source Structure in 0.15 micron SOI MOSFETs Using Two Dimensional Device Simulation Reviewed
Arisumi, Matsuzawa, Shigyo, Terauchi, Nishiyama, Yoshimi
Japanese Journal of Applied Physics 35 992 - 995 1996.4
Joint Work
We describe the technological potential of the bandgap engineering technique involving a Si-Ge source structure in a fully-depleted SOI MOSFET to suppress the'floating-body effect. The Si-Ge layer fabricated in the source region acts as an absorber for excess holes in the channel region. The detailed .mechanism as well as the structure dependence in SOI MOSFETs with a gate length of 0.15 μm have been studied using a two-dimensional device simulation. It has been found that the imprpvement in BVds is strongly dependent on the lateral position of the Si-Ge layer relative to the source-to-channel pn junction. It is further predicted that encroachment of the Si-Ge layer into the channel region achieves the maximum BVds improvement. The BVds improvement is predicted to reach 1.5 V if it proves possible to lower the energy barrier at the pn junction in the case where tlEg = 0.2 eV.
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Formation of SiGe Source/Drain Using Ge Implantation for Floating-Body Effect Resistant SOI MOSFETs Reviewed
Nishiyama, Arisumi, Terauchi, Takeno, Suzuki, Takakuwa, Yoshimi
Japanese Journal of Applied Physics 35 954 - 959 1996.4
Joint Work
SiGe was formed by Ge implantation into silicon on insulator (SOI) substrates with the dosage range from 0.5 to 3 X 1016 cm-2 and subsequent annealing in N2 . The implantation dosage dependence of the crystalline quality, bandgap and sheet resistance of the SiGe layers are investigated. The implantation damage for Ge dosage up to 1 X 1016 cm-2 can be removed at a temperature as low as 700°C. A SiGe crystalline network is formed by the annealing at the same time. With a Ge dosage of 1 x 1016 cm-2 or more, bandgap narrowing of the SiGe layer was detected. Sheet resistances of SiGe N+ and p+ layers gradually increase for higher Ge dosage. SOI MOSFET characteristics in terms of the floating-body effect with the SiGe source/drain layers are presented. The bandgap narrowing suppresses the floating-body effect of fully depleted SOI MOSFETs, while maintaining the reverse leakage current of the p-n junction between the source/drain and channel at a low level.
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0.5V SOI CMOS Pass-Gate Logic Reviewed
Fuse, Oowaki, Terauchi, Watanabe, Yoshimi, Oouchi, Matsunaga
Digest of Technical Papers, 1996 IEEE International Solid-State Circuits Conference 88 - 89 1996.2
Joint Work
Demand for low-power ULSIs for mobile electronic equipment is increasing rapidly. To reduce power consumption, lower operating voltage and minimized device size (or count) is essential. To lower the actual threshold voltage and lower the operation voltage, SOI MOSFET with gate-body connection is proposed. However, the circuit architecture that affords the maximum advantage of the body controlled SOI MOSFET has not yet been reported. The SOI CMOS pass-gate logic described here offers the lowest operation voltage and reduced transistor dimensions. In this logic the body of the SOI pass-gate is connected to the input signal given to the gate. Low threshold voltage for the onstate pass-gate and high threshold voltage for the off-state passgate is realized, and the increase in the threshold voltage due to the body-effect is suppressed. Two types of buffer suitable for SOI pass-gate logic are examined.
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Bandgap Engineering Technology for Suppressing the Floating-Body-Effect in 0.15 mm SOI-MOSFET Reviewed
Yoshimi, Nishiyama, Terauchi, Arisumi, Murakoshi, Ushiku, Takeno, Suzuki
Technical Digest of 1995 IEEE International SOI Conference 80 - 81 1995.10
Joint Work
The substrate floating effect is the most fundamental problem in SOI-MOSFETs. Conventional countermeasures, such as body-contact, LDD structure are accompanied by area penalty, Id degradation and other drawbacks. To suppress this effect, we have proposed the bandgap engineering method, in which a narrow bandgap material is formed in the source region. In this paper, an ideal structure for the bandgap engineering is discussed and actually achievable performance is estimated based on simulations and experiments for 0.15 /spl mu/m SOI-MOSFETs.
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Formation of SiGe Source/Drain Using Ge Implantation for Floating-Body Effect Resistant SOI MOSFETs Reviewed
Nishiyama, Arisumi, Terauchi, Yoshimi, Takeno, Suzuki
Extended Abstracts of the 1995 International Conference on Solid State Devices and Materials 545 - 547 1995.9
Joint Work
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Analysis of Si-Ge Source Structure in 0.15 micron SOI MOSFETs Using Two-Dimensional Device Simulation Reviewed
Arisumi, Matsuzawa, Shigyo, Terauchi, Nishiyama, Yoshimi
Extended Abstracts of the 1995 International Conference on Solid State Devices and Materials 860 - 862 1995.9
Joint Work
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Suppression of the Floating-Body Effects in SOI MOSFETs by Bandgap Engineering Reviewed
Mamoru Terauchi, Makoto Yoshimi, Atsushi Murakoshi, Yukihiro Ushiku
Digest of Technical Papers, 1995 Symposium on VLSI Technology 35 - 36 1995.6
Joint Work
Authorship：Lead author
The floating-body effects, which are regarded as the most critical issues in applying Silicon-On-Insulator (SOI) devices to actual LSIs, can be suppressed by the reduction in bandgap energy in the source region. In addition to an increase in the drain breakdown voltage, the suppression of both kinks in I/sub d/-V/sub d/ characteristics and threshold voltage shift with an increase in drain voltage are achieved in sub-quarter micron Nch thin-film SOI MOSFETs.
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Technology Trends of Silicon-On-Insulator -Its Advantages and Problems to be Solved- Reviewed
Yoshimi, Terauchi, Murakoshi, Koh, Matsuzawa, Shigyo, Ushiku
Digest of Technical Papers, 1994 IEEE Electron Devices Meeting 429 - 432 1994.12
Joint Work
Recent progress in SOI technology is reviewed and problems which need be solved are discussed. Emphasis is placed on the substrate floating effect, for which the bandgap engineering method is proposed for the first time. It is demonstrated that Si-Ge formation in the source region can improve the drain breakdown voltage significantly.
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A Surrounding Gate Transistor (SGT) Gain Cell for Ultra High Density DRAMs Reviewed
Mamoru Terauchi, Akihiro Nitayama, Fumio Horiguchi, Fujio Masuoka
Digest of Technical Papers, 1993 Symposium on VLSI Technology 21 - 22 1993.6
Joint Work
Authorship：Lead author
Conventionally, it is necessary to obtain enough (eg. 30fF per one cell) storage capacitance in as small a area as possible. In order to realize high density DRAMs, this leads to the employment of very deep trench- or complicated stacked-capacitors, which elongates fabrication processes. On the other hand, read-out voltage in a conventional DRAM cell is so small that the folded bit-line (BL) scheme must be utilized. In order to reduce noise voltage due to the so-called array-noise, the minimum cell size in this scheme is 8F^2 (F: feature size), which Is larger than that (6F^2) in the open BL scheme. Both the elongated fabrication processes and the 1arge cell size may augment the fabrication cost to be an intolerable amount as F is going to be scaled down to lower sub-micron dimension.
In order to overcome these cost-related problems, the authors propose an easy-to-make, and extremely small, new gain cell structure based on Surrounding Gate Transistor (SGT) [1-3]. Since it operates as a gain cell, it ls possible to read out sufficient amount of signal charge regardless of the stored amount. Thus the storage capacitance needed to realize enough retention time can be much smaller than that required for the conventional trench/stacked DRAM cells. Therefore the open BL scheme can be used for this SGT gain cell because there ls no noise-related problem. In addition, Its cell size is reduced to be 4F.- since It can be arranged to have the cross-point-type configuration. It ls much smaller than other gain cells such as SEA cell [4] or CG cell [5]. Therefore this gain cell ls a promising candidate cell structure for 1G bit/4G bit DRAMs. -
Primary Processes in Sensory Rhodopsin and Retinochrome Reviewed
Kobayashi, Ohtani, Tsuda, Ogasawara, Koshihara, Ichimura, Hara, Terauchi
Plenum Photobiological Science: Its Application 561 - 570 1991.4
Joint Work
hotochemistry of two chromoproteins with retinal have been studied. One is a photoreceptor for the phototaxis of Halobacterium halobium and the other is a photosensitive pigment contained in cephalopod visual cells. The behaviors of the intermediates in their photocycles were clarified with picosecond and nanosecond timeresolved absorption spectroscopy apparatuses.
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Femtosecond Spectroscopy of Acidified Bacteriorhodopsin Reviewed
Takayoshi Kobayashi, Mamoru Terauchi, Masayuki Yoshizawa, Makoto Taiji, Tsutomu Kouyama
Proceedings of 1990 International Quantum Electronics Conference 182 - 182 1990.6
Joint Work
Bacteriorhodopsin (bR) is a ligh t-harvesting energy-transducing pigment so far found only in Halobacterium halobium, prokaryotes that occur in natural brines where the NaCl concentration is at or near saturation.1 Its chromophore, retinal (vitamin A aldehyde), is bound via protonated Schiff base linkage to the E group of a lysine-216 residue in the 26,000-mol wt. protein.2 At neutral pH, bR exhibits a purple color and becomes blue in the acidic environment.1
Because the acidic form of bR (bR605) is an ~40:60 mixture of 13-cis bR605 and all-trans bR605 and neither 13-cis bR605 nor all-trans bR605 can be isolated from each other, there are few papers concerning the photocycles of bR605 including our early picosecond experiment.3
The primary photoprocesses of bR605 studied for the first time, we believe, by femtosecond absorption spectroscopy are described. It has been found that the lowest excited singlet states of 13-cis and all-trans bR605 have different lifetimes (1.5 ± 0.2 ps for 13-cis bR605 and 8.6 ± 0.9 ps for all-trans bR605) from each other and that the red shifted ground state intermediate so far reported in the nanosecond time scale Kacid is directly formed from the lowest excited singlet states of bR605; i.e., there is no species that corresponds to J625, which is the first red shifted ground state intermediate in the photocycle of light adapted bacteriorhodopsin at neutral pH (bR568) in the photocycle of bR605. It has also been found that, because there was no clear oscillatory behavior in the transient gain or absorption associated with the transition from the lowest excited singlet states of bR605, the isomerization around C13=C14 of the retinal molecule in the lowest excited singlet states in both 13-cis bR605 and all-trans bR605 has an overdamped nature; i.e., the isomerization angle varies only monotonously in the lowest excited singlet states of both 13-cis bR605 and all-trans bR605. -
Femtosecond Spectroscopy of Acidified and Neutral Bacteriorhodopsin Reviewed
Takayoshi Kobayashi, Mamoru Terauchi, Tsutomu Kouyama, Masayuki Yoshizawa, Makoto Taiji
SPIE Laser Applications in Life Science 1403 407 - 416 1990.5
Joint Work
Femtosecond time-resolved spectroscopic measurements were performed over a wide spectral range of 450-900 nm for the acidic state (bR605) and neutral state (bR568) of bacteriorhodopsin, and their initial photoprocesses were compared. In the neutral state, the induced emission at 860 nm and the excited-state absorption at 480 nm decayed simultaneously with a time constant of 500 fs. This result supports the previous report that the transient absorption species at 460 nm corresponds to the S1 state of bR568. In the acidic state, the decay of induced emission at 860 nm and excited-state absorption at 480 nm were described by two time constants of 1.5 ± 0.2 ps and 8.6 ± 0.9 ps. These two components are estimated to be due to two isomers present in the acidic state. In the acidic state, no time-dependent vibrational structure was observed in the induced emission or excited-state absorption. From these experimental results, it is evident that the isomerization around the C13-C14 bond of the retinal molecule in the S1 state can be described by overdamped vibration. In other words, in the S1 state, the isomerization angle changes monotonically.
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Primary Photoprocesses in Bacteriorhodopsin and Octopus Rhodopsin by Time-Resolved Spectroscopy
Mamoru Terauchi
Doctor's thesis 1990.3
Single Work
Femtosecond time-resolved spectroscopic measurements were performed over a wide spectral range of 450-900 nm for the acidic state (bR605) and neutral state (bR568) of bacteriorhodopsin, the light-sensitive protein of the halophilic archaeon Halobacterium halobium. The results showed that the transient absorption species correspond to the S1 state of bR568 for the neutral state. For the acidic state, a two-component transient response was observed, which is estimated to be due to two isomers present in the acidic state. Additionally, it was revealed that the isomerization angle around the carbon backbone C13-C14 of the retinal molecule in the S1 state changes monotonically with time.
Furthermore, nanosecond time-resolved spectroscopy of halorhodopsin was conducted, and the temperature dependence of its light-induced initial process reverse reaction was investigated to determine in which reaction process the conformational change of rhodopsin is maximized. -
Picosecond Absorption Spectra of a Reaction Center from a Novel Thermophilic Photosynthetic Bacterium 'Chromatium tepidum' Reviewed
Nozawa, Terauchi, Kobayashi, Hatano
Springer Series in Chemical Physics 48 606 - 609 1988.10
Joint Work
Picosecond transient absorption spectroscopy has been applied to a new reaction center purified from a novel thermophilic photosynthetic bacterium Chromatium tepidum. Although the ground state spectrum of the reaction center shows significant differences from that of a mesophilic purple bacterium (Rhodobacter sphaeroides R-26), the primary charge separation kinetics in the reaction center of C. tepidum were essentially the same as those of R. sphaeroides R-26. The significant differences in the ground state spectra are reflected in the profile of the transient absorption spectra. Futhermore electronic transition assignments were discussed.
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Nosaka, Miyama, Terauchi, Kobayashi
Journal of Physical Chemistry 92 255 - 256 1988.10
Joint Work
Study of semiconductor particles is attractive because of possible applications for the direct conversion of solar energy into chemical energy.1 Therefore, it seems important to investigate the processes such as interfacial electron transfer and electron-hole recombination occurring at illuminated semiconductor colloidal particles. For that purpose, time-resolved laser spectroscopy for transparent colloidal semiconductor solution is very useful.1 2 Serpone and co-workers3 first reported picosecond absorption spectra of reduced methylvlologen (MV*+) on illuminated colloidal CdS and claimed that the photoinduced electron transfer from CdS to methylviologen (MV2+) occurred at the rate of 109 s™1. Rossetti and Brus4 reported that the rise time of MV’+ radical is between 5 ns and 20 ps from a picosecond resonance Raman scattering study. Recently, Ramsden5 6has reported that MV2+ is not adsorbed on colloidal CdS stabilized with sodium hexametaphosphate (HMP) from the analysis of nanosecond laser flash photolysis.
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Picosecond Absorption Spectra of a Reaction Center from a Novel Thermophilic Photosynthetic Bacterium 'Chromatium tepidum' Reviewed
Nozawa, Hatano, Terauchi, Kobayashi, Trost, Blankenship
Proceedings of 1988 International Conference on Ultrafast Phenomena 172 - 173 1988.8
Joint Work
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Mamoru Terauchi, Takayoshi Kobayashi
Chemical Physics Letters 137 319 - 323 1987.10
Joint Work
Authorship：Lead author
Laser tuning spectra, nanosecond gain spectra, and picosecond gain and absorption spectra of 1-[p-(N,N-dimethyl-amino)phenyl]-4-(p-nitrophenyl)-1,3-butadiene (DMANPB) are reported. Its permanent dipole moment is found to be larger than 30 D in the lowest excited singlet state. The tuning ranges are 690–725, 695–745, and 705–755 nm in dioxane-acetone mixed solution with volume ratios of 1:0, 5:1, and 4:1, respectively.
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Takayoshi Kobayashi, Hiroyuki Ohtani, Kenji Kurokawa, Mamoru Terauchi
Proceedings of 1987 International Quantum Electronics Conference 114 - 115 1987.10
Joint Work
Stilbene derivatives with electron-donative group(s) attached to one benzene ring and electron-acceptive group(s) to the other are interesting molecules with respect to their large nonlinear optical properties associated with their giant permanent dipole moments, especially in the excited singlet states. One such molecule is 4-dimethyla- mino-4'-nitrostilbene (DMANS), which is reported to have a very large dipole moment (32 D) in the lowest excited singlet state.1 We have proposed the possibility of the application of such molecular systems as DMANS and its diethyl derivative, 4-diethylamino-4'-nitrostilbene (DEANS), which has higher solubility than DMANS in various solvents, to the optically bistable devices utilizing their large third-order nonlinear susceptibility induced by the large dipole moments.2,3
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Lasing Properties and Gain Spectrum of 4-Diethylamino-4'-Nitrostilbene with a Giant Permanent Dipole Reviewed
Takayoshi Kobayashi, Mamoru Terauchi, Hisao Uchiki
Chemical Physics Letters 126 143 - 148 1986.10
Joint Work
Lasing properties are reported for 4-diethylamino-4'-nitrostilbene (DEANS), which has a giant permanent dipole moment in the lowest excited singlet state. Tuning ranges are 612–650 nm, 647–705 nm, 653–708 nm, and 680–705 nm in benzene-acetone mixed solution with volume ratios of 1:0, 5:1, 4:1, and 3:1, respectively. Nanosecond gain and laser spectra measured for DEANS in benzene are also reported.