Pub Date : 2024-01-04DOI: 10.35848/1347-4065/ad1005
Wataru Miyazaki, Hajime Tanaka, Nobuya Mori
The effects of strain on the carrier transport in gallium nitride (GaN) are investigated using a full-band Monte Carlo method combined with an empirical tight-binding method. The impacts on the carrier mobility, carrier drift velocity, and breakdown characteristics are discussed. Compressive uniaxial or tensile biaxial strain is beneficial for achieving higher hole mobility in vertical GaN devices due to the light-hole band being lifted above the heavy-hole band. Analysis of the breakdown phenomena indicates that strain does not degrade the breakdown characteristics in terms of its effect on the band structure.
{"title":"Full-band Monte Carlo analysis of strain effects on carrier transport in GaN","authors":"Wataru Miyazaki, Hajime Tanaka, Nobuya Mori","doi":"10.35848/1347-4065/ad1005","DOIUrl":"https://doi.org/10.35848/1347-4065/ad1005","url":null,"abstract":"The effects of strain on the carrier transport in gallium nitride (GaN) are investigated using a full-band Monte Carlo method combined with an empirical tight-binding method. The impacts on the carrier mobility, carrier drift velocity, and breakdown characteristics are discussed. Compressive uniaxial or tensile biaxial strain is beneficial for achieving higher hole mobility in vertical GaN devices due to the light-hole band being lifted above the heavy-hole band. Analysis of the breakdown phenomena indicates that strain does not degrade the breakdown characteristics in terms of its effect on the band structure.","PeriodicalId":14741,"journal":{"name":"Japanese Journal of Applied Physics","volume":"9 1","pages":""},"PeriodicalIF":1.5,"publicationDate":"2024-01-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139092255","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-01-04DOI: 10.35848/1347-4065/ad0e27
Johji Nishio, Chiharu Ota, Ryosuke Iijima
The expansion rate of single Shockley-type stacking faults (1SSFs) was examined in 4H-SiC under UV illumination in various basal plane dislocation (BPD) structures with 90° or 30° Si-core partial dislocations (PDs) at the expansion front. In the case of 30° Si-core PDs at the front, we found some BPDs with extremely slow expansion rates. Photoluminescence imaging revealed that the BPDs were accompanied by characteristic dim lines in the shallower parts of the epitaxial layers. We confirmed that the lines were threading edge dislocations by transmission electron microscopy. Additional high-resolution scanning transmission electron microscope analysis revealed that the leading partial was a 30° C-core instead of a 30° Si-core. This implies the large amount of C-core segments on the expanding PD might be the reason for the 1SSFs having very slow expansion rates. Moreover, the expansion rate of 90° Si-core PDs was obtained experimentally and compared with that of 30° PDs.
在紫外光照射下，我们研究了 4H-SiC 中各种基底面位错（BPD）结构中单肖克利型堆叠断层（1SSFs）的扩展速率，这些结构的扩展前沿具有 90° 或 30° Si 核部分位错（PDs）。在前端有 30° Si 核部分位错的情况下，我们发现一些 BPD 的膨胀速度极慢。光致发光成像显示，BPD 在外延层的较浅部分伴有特征性的暗线。我们通过透射电子显微镜确认这些线条是穿线边缘位错。另外的高分辨率扫描透射电子显微镜分析表明，前沿部分是 30° C 型芯，而不是 30° Si 型芯。这意味着膨胀 PD 上的大量 C 核段可能是 1SSF 膨胀率非常慢的原因。此外，实验还获得了 90° Si 核 PD 的膨胀率，并与 30° PD 的膨胀率进行了比较。
{"title":"Effect of basal plane dislocation structures on single Shockley-type stacking fault expansion rate in 4H-SiC","authors":"Johji Nishio, Chiharu Ota, Ryosuke Iijima","doi":"10.35848/1347-4065/ad0e27","DOIUrl":"https://doi.org/10.35848/1347-4065/ad0e27","url":null,"abstract":"The expansion rate of single Shockley-type stacking faults (1SSFs) was examined in 4H-SiC under UV illumination in various basal plane dislocation (BPD) structures with 90° or 30° Si-core partial dislocations (PDs) at the expansion front. In the case of 30° Si-core PDs at the front, we found some BPDs with extremely slow expansion rates. Photoluminescence imaging revealed that the BPDs were accompanied by characteristic dim lines in the shallower parts of the epitaxial layers. We confirmed that the lines were threading edge dislocations by transmission electron microscopy. Additional high-resolution scanning transmission electron microscope analysis revealed that the leading partial was a 30° C-core instead of a 30° Si-core. This implies the large amount of C-core segments on the expanding PD might be the reason for the 1SSFs having very slow expansion rates. Moreover, the expansion rate of 90° Si-core PDs was obtained experimentally and compared with that of 30° PDs.","PeriodicalId":14741,"journal":{"name":"Japanese Journal of Applied Physics","volume":"94 1","pages":""},"PeriodicalIF":1.5,"publicationDate":"2024-01-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139092258","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-01-04DOI: 10.35848/1347-4065/ad0dbc
Riku Okumura, Takeo Oku, Atsushi Suzuki
A monovalent copper ion (Cu+) with the same valence as formamidinium is focused on the present work, and the effects of A-site inorganic cations on the electronic structures and device performance are discussed from the experiments and the first-principles calculations. The addition of inorganic cations increased the conversion efficiencies, and the copper-doped device showed the highest conversion efficiency. In particular, the hysteresis of current density–voltage characteristics was significantly suppressed by the addition of Cu+, which would be due to suppression of iodine ion (I−) diffusion by electrostatic interaction between Cu+ and I−. The addition of rubidium or cesium contributed to the increase in short-circuit current density by suppressing decomposition of perovskite crystals and formation of PbI2.
{"title":"Effects of alkali metals or Cu+ addition to α-FAPbI3 perovskite crystals on electronic structures and photovoltaic properties","authors":"Riku Okumura, Takeo Oku, Atsushi Suzuki","doi":"10.35848/1347-4065/ad0dbc","DOIUrl":"https://doi.org/10.35848/1347-4065/ad0dbc","url":null,"abstract":"A monovalent copper ion (Cu<sup>+</sup>) with the same valence as formamidinium is focused on the present work, and the effects of A-site inorganic cations on the electronic structures and device performance are discussed from the experiments and the first-principles calculations. The addition of inorganic cations increased the conversion efficiencies, and the copper-doped device showed the highest conversion efficiency. In particular, the hysteresis of current density–voltage characteristics was significantly suppressed by the addition of Cu<sup>+</sup>, which would be due to suppression of iodine ion (I<sup>−</sup>) diffusion by electrostatic interaction between Cu<sup>+</sup> and I<sup>−</sup>. The addition of rubidium or cesium contributed to the increase in short-circuit current density by suppressing decomposition of perovskite crystals and formation of PbI<sub>2</sub>.","PeriodicalId":14741,"journal":{"name":"Japanese Journal of Applied Physics","volume":"19 1","pages":""},"PeriodicalIF":1.5,"publicationDate":"2024-01-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139092298","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
We conducted thermodynamic analysis and kinetics calculations for hexachlorodisilane (Si2Cl6), which is used as source gas for the CVD of silicon nitride films. Thermodynamic analysis clarified Si2Cl6 decomposes almost completely to SiCl4 and SiCl2 in the range of 600 °C–1100 °C under equilibrium condition. Therefore, it is estimated that the main gas-phase reaction of Si2Cl6 is represented by the reaction Si2Cl6 → SiCl4 + SiCl2. Thermodynamic analysis also shows that the Si2Cl6 system has a larger equilibrium partial pressure of SiCl2 than SiHxCl4-x (x = 1 ~ 3) systems. Kinetics calculations revealed Si2Cl6 decomposes by 90% in 0.11 s at 600 °C, and 0.55 × 10−3 s at 800 °C, respectively. The time-dependent pyrolysis ratio of Si2Cl6 becomes larger as the total pressure decreases at 600 °C. On the other hand, the ratio is almost the same regardless of total pressure at 800 °C. These results will help optimize CVD process conditions using Si2Cl6.
{"title":"Theoretical study of the gas-phase reaction of hexachlorodisilane by thermodynamic analysis and kinetics calculation","authors":"Tomoya Nagahashi, Hajime Karasawa, Ryota Horiike, Kenji Shiraishi","doi":"10.35848/1347-4065/ad0fa0","DOIUrl":"https://doi.org/10.35848/1347-4065/ad0fa0","url":null,"abstract":"We conducted thermodynamic analysis and kinetics calculations for hexachlorodisilane (Si<sub>2</sub>Cl<sub>6</sub>), which is used as source gas for the CVD of silicon nitride films. Thermodynamic analysis clarified Si<sub>2</sub>Cl<sub>6</sub> decomposes almost completely to SiCl<sub>4</sub> and SiCl<sub>2</sub> in the range of 600 °C–1100 °C under equilibrium condition. Therefore, it is estimated that the main gas-phase reaction of Si<sub>2</sub>Cl<sub>6</sub> is represented by the reaction Si<sub>2</sub>Cl<sub>6</sub> → SiCl<sub>4</sub> + SiCl<sub>2</sub>. Thermodynamic analysis also shows that the Si<sub>2</sub>Cl<sub>6</sub> system has a larger equilibrium partial pressure of SiCl<sub>2</sub> than SiH<sub>x</sub>Cl<sub>4-x</sub> (x = 1 ~ 3) systems. Kinetics calculations revealed Si<sub>2</sub>Cl<sub>6</sub> decomposes by 90% in 0.11 s at 600 °C, and 0.55 × 10<sup>−3 </sup>s at 800 °C, respectively. The time-dependent pyrolysis ratio of Si<sub>2</sub>Cl<sub>6</sub> becomes larger as the total pressure decreases at 600 °C. On the other hand, the ratio is almost the same regardless of total pressure at 800 °C. These results will help optimize CVD process conditions using Si<sub>2</sub>Cl<sub>6</sub>.","PeriodicalId":14741,"journal":{"name":"Japanese Journal of Applied Physics","volume":"37 1","pages":""},"PeriodicalIF":1.5,"publicationDate":"2024-01-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139092632","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Polarized terahertz (THz) sources are important components in THz technologies. This paper highlights and discusses recent progress and measurement methods in the monolithic generation of polarized THz radiation using intrinsic Josephson junction oscillators made of high-Tc superconductors. The polarized radiation is generated from three mesa designs: truncated-edge square, notched cylindrical, and rectangular mesa structures. The polarization control depends on the excitation of two orthogonal TM modes in these mesas, comprising stacked intrinsic Josephson junctions in single crystalline Bi2Sr2CaCu2O8+δ. This method maintains a high output intensity and low axial ratios while avoiding the signal loss associated with external polarimetric modulators prevalent in the THz frequency range. Moreover, it demonstrates the manipulation of terahertz wave helicity by adjusting the current injection position, with experiments substantiating the device’s capability to switch between left-handed and right-handed elliptical polarization at designated frequencies.
{"title":"Polarized terahertz electromagnetic-wave radiation from cuprate superconductor Bi2212 mesa structures","authors":"Asem Elarabi, Yoshito Saito, Hidehiro Asai, Ryota Kobayashi, Ken Hayama, Keiichiro Maeda, Shuma Fujita, Yusuke Yoshioka, Yoshihiko Takano, Manabu Tsujimoto, Itsuhiro Kakeya","doi":"10.35848/1347-4065/ad0cdd","DOIUrl":"https://doi.org/10.35848/1347-4065/ad0cdd","url":null,"abstract":"Polarized terahertz (THz) sources are important components in THz technologies. This paper highlights and discusses recent progress and measurement methods in the monolithic generation of polarized THz radiation using intrinsic Josephson junction oscillators made of high-<italic toggle=\"yes\">T</italic>\u0000<sub>\u0000<italic toggle=\"yes\">c</italic>\u0000</sub> superconductors. The polarized radiation is generated from three mesa designs: truncated-edge square, notched cylindrical, and rectangular mesa structures. The polarization control depends on the excitation of two orthogonal TM modes in these mesas, comprising stacked intrinsic Josephson junctions in single crystalline Bi<sub>2</sub>Sr<sub>2</sub>CaCu<sub>2</sub>O<sub>8+<italic toggle=\"yes\">δ</italic>\u0000</sub>. This method maintains a high output intensity and low axial ratios while avoiding the signal loss associated with external polarimetric modulators prevalent in the THz frequency range. Moreover, it demonstrates the manipulation of terahertz wave helicity by adjusting the current injection position, with experiments substantiating the device’s capability to switch between left-handed and right-handed elliptical polarization at designated frequencies.","PeriodicalId":14741,"journal":{"name":"Japanese Journal of Applied Physics","volume":"266 1","pages":""},"PeriodicalIF":1.5,"publicationDate":"2024-01-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139096590","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-01-04DOI: 10.35848/1347-4065/ad1006
Kiyofumi Yamagiwa, Kyohei Kamimura, Yuuri Kimura
Highly dispersed Pt nanoparticles supported on polyacrylonitrile-based carbon fiber substrates were prepared using a one-step liquid-phase process. Nanoparticles were grown on the fiber surface via electric resistance heating of the substrate in ethanol solutions containing a platinum-based organometallic complex as the nanoparticle precursor. After the synthesis, Pt nanoparticles were formed on the surface in highly dispersed states. Electrochemical characterization of the Pt nanoparticles was conducted using the substrates directly after synthesis. The Pt nanoparticles were electrochemically active and exhibited superior methanol oxidation properties.
{"title":"One-step liquid-phase synthesis of platinum nanocatalysts supported on carbon fiber substrates and their electrochemical characterization","authors":"Kiyofumi Yamagiwa, Kyohei Kamimura, Yuuri Kimura","doi":"10.35848/1347-4065/ad1006","DOIUrl":"https://doi.org/10.35848/1347-4065/ad1006","url":null,"abstract":"Highly dispersed Pt nanoparticles supported on polyacrylonitrile-based carbon fiber substrates were prepared using a one-step liquid-phase process. Nanoparticles were grown on the fiber surface via electric resistance heating of the substrate in ethanol solutions containing a platinum-based organometallic complex as the nanoparticle precursor. After the synthesis, Pt nanoparticles were formed on the surface in highly dispersed states. Electrochemical characterization of the Pt nanoparticles was conducted using the substrates directly after synthesis. The Pt nanoparticles were electrochemically active and exhibited superior methanol oxidation properties.","PeriodicalId":14741,"journal":{"name":"Japanese Journal of Applied Physics","volume":"3 1","pages":""},"PeriodicalIF":1.5,"publicationDate":"2024-01-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139096361","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
In this work, we present the biquadratic field Hbq contribution to increase a frequency of spin-torque oscillation (STO) in an orthogonal magnetization structure in simulation, and realize such an orthogonal structure by preparing Co/Pt lamination as the bottom perpendicular magnetic anisotropy layer, Cr or Cu as the spacer, and experimentally realize Fe90Co10 as the top free layer. Our observations of the Cr-spacer sample reveal a notable challenge in achieving magnetic saturation, underscoring the role of Hbq in suppressing magnetization reversal and its potential to broaden the STO current range and increase the STO frequency. This leads to the manifestation of spin-transfer-torque oscillations in an orthogonal structure, bolstered by robust biquadratic magnetic coupling, thus attaining high and stable STOs in the simulations.
在这项工作中，我们提出了在正交磁化结构中提高自旋扭矩振荡（STO）频率的模拟双向场 Hbq 贡献，并通过制备 Co/Pt 层压作为底部垂直磁各向异性层、Cr 或 Cu 作为间隔层以及实验实现 Fe90Co10 作为顶部自由层来实现这种正交结构。我们对铬-间隔层样品的观察结果表明，在实现磁饱和方面存在明显挑战，这突出了 Hbq 在抑制磁化反转方面的作用，以及它在拓宽 STO 电流范围和提高 STO 频率方面的潜力。这导致了正交结构中自旋转移力矩振荡的出现，并得到了强大的双四边形磁耦合的支持，从而在模拟中实现了高而稳定的 STO。
{"title":"Biquadratic magnetic coupling effect in CoPt/Cr/Fe90Co10 orthogonal structures","authors":"Chuhan Liu, Yuichiro Kurokawa, Naoki Hashimoto, Terumitsu Tanaka, Hiromi Yuasa","doi":"10.35848/1347-4065/ad0e28","DOIUrl":"https://doi.org/10.35848/1347-4065/ad0e28","url":null,"abstract":"In this work, we present the biquadratic field <bold>H</bold>\u0000<sub>\u0000<bold>bq</bold>\u0000</sub> contribution to increase a frequency of spin-torque oscillation (STO) in an orthogonal magnetization structure in simulation, and realize such an orthogonal structure by preparing Co/Pt lamination as the bottom perpendicular magnetic anisotropy layer, Cr or Cu as the spacer, and experimentally realize Fe<sub>90</sub>Co<sub>10</sub> as the top free layer. Our observations of the Cr-spacer sample reveal a notable challenge in achieving magnetic saturation, underscoring the role of <bold>H</bold>\u0000<sub>\u0000<bold>bq</bold>\u0000</sub> in suppressing magnetization reversal and its potential to broaden the STO current range and increase the STO frequency. This leads to the manifestation of spin-transfer-torque oscillations in an orthogonal structure, bolstered by robust biquadratic magnetic coupling, thus attaining high and stable STOs in the simulations.","PeriodicalId":14741,"journal":{"name":"Japanese Journal of Applied Physics","volume":"173 1","pages":""},"PeriodicalIF":1.5,"publicationDate":"2024-01-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139092157","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The effects of soft X-ray irradiation and atomic hydrogen annealing on the reduction of graphene oxide (GO) to obtain graphene were investigated. To clarify the interaction between soft X-rays and GO, soft X-rays of 300 eV and 550 eV were used for C 1s and O 1s inner-shell electron excitation, respectively at the NewSUBARU synchrotron radiation facility. Low-temperature reduction of the GO film was achieved by using soft X-ray at temperatures below 150 °C at 300 eV, and 60 °C at 550 eV. O-related peaks in X-ray photoelectron spectroscopy, such as the C–O–C peak, were smaller at 550 eV than those at 300 eV. This result indicates that excitation of the core–shell electrons of O enhances the reduction of GO. Soft X-rays preferentially break C–C and C–O bonds at 300 and 550 eV, respectively.
研究了软 X 射线辐照和原子氢退火对氧化石墨烯（GO）还原获得石墨烯的影响。为了明确软 X 射线与 GO 之间的相互作用，在 NewSUBARU 同步辐射设施中分别使用 300 eV 和 550 eV 的软 X 射线进行 C 1s 和 O 1s 内壳电子激发。通过使用软 X 射线，在低于 150 ℃（300 eV）和 60 ℃（550 eV）的温度下实现了 GO 薄膜的低温还原。X 射线光电子能谱中与 O 有关的峰，如 C-O-C 峰，在 550 eV 下比 300 eV 下的峰更小。这一结果表明，激发 O 的核壳电子会增强 GO 的还原性。软 X 射线在 300 和 550 eV 分别优先打断 C-C 和 C-O 键。
{"title":"Photon energy dependence of graphene oxide reduction by soft X-ray irradiation and atomic hydrogen annealing","authors":"Akira Heya, Akinori Fujibuchi, Masahiro Hirata, Yoshiaki Matsuo, Junichi Inamoto, Kazuhiro Kanda, Koji Sumitomo","doi":"10.35848/1347-4065/ad0cdf","DOIUrl":"https://doi.org/10.35848/1347-4065/ad0cdf","url":null,"abstract":"The effects of soft X-ray irradiation and atomic hydrogen annealing on the reduction of graphene oxide (GO) to obtain graphene were investigated. To clarify the interaction between soft X-rays and GO, soft X-rays of 300 eV and 550 eV were used for C 1s and O 1s inner-shell electron excitation, respectively at the NewSUBARU synchrotron radiation facility. Low-temperature reduction of the GO film was achieved by using soft X-ray at temperatures below 150 °C at 300 eV, and 60 °C at 550 eV. O-related peaks in X-ray photoelectron spectroscopy, such as the C–O–C peak, were smaller at 550 eV than those at 300 eV. This result indicates that excitation of the core–shell electrons of O enhances the reduction of GO. Soft X-rays preferentially break C–C and C–O bonds at 300 and 550 eV, respectively.","PeriodicalId":14741,"journal":{"name":"Japanese Journal of Applied Physics","volume":"70 1","pages":""},"PeriodicalIF":1.5,"publicationDate":"2024-01-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139092239","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-01-04DOI: 10.35848/1347-4065/ad1004
Che-Chuan Liu, Hsin-Yi Shen, Kuangye Wang, Yu-Lun Chueh, Yue-Der Chih, Jonathan Chang, Jiaw-Ren Shih, Chrong-Jung Lin, Ya-Chin King
This research presents a gas sensor system featuring a selenized two-dimensional (2D) film as its primary sensing material, integrated with metal-gate-coupled floating gate devices to enable self-convergent calibration. The inherent variability in resistance levels of 2D gas-sensing materials across different devices has been a significant challenge, resulting in substantial deviations of the output signal within the sensing circuit. To address this issue, we introduce a novel self-convergent operational technique, which effectively mitigates the impact of resistance variations thereby enhancing the precision and reliability of gas-sensing outcomes. The proposed gas sensor system promises to deliver consistent and accurate results, even with device-to-device resistance variations, making it a valuable contribution to gas-sensing technology. This work holds substantial potential for various applications requiring highly precise gas detection and quantification.
{"title":"Advanced self-convergent calibration for selenized two-dimensional film gas sensors","authors":"Che-Chuan Liu, Hsin-Yi Shen, Kuangye Wang, Yu-Lun Chueh, Yue-Der Chih, Jonathan Chang, Jiaw-Ren Shih, Chrong-Jung Lin, Ya-Chin King","doi":"10.35848/1347-4065/ad1004","DOIUrl":"https://doi.org/10.35848/1347-4065/ad1004","url":null,"abstract":"This research presents a gas sensor system featuring a selenized two-dimensional (2D) film as its primary sensing material, integrated with metal-gate-coupled floating gate devices to enable self-convergent calibration. The inherent variability in resistance levels of 2D gas-sensing materials across different devices has been a significant challenge, resulting in substantial deviations of the output signal within the sensing circuit. To address this issue, we introduce a novel self-convergent operational technique, which effectively mitigates the impact of resistance variations thereby enhancing the precision and reliability of gas-sensing outcomes. The proposed gas sensor system promises to deliver consistent and accurate results, even with device-to-device resistance variations, making it a valuable contribution to gas-sensing technology. This work holds substantial potential for various applications requiring highly precise gas detection and quantification.","PeriodicalId":14741,"journal":{"name":"Japanese Journal of Applied Physics","volume":"14 1","pages":""},"PeriodicalIF":1.5,"publicationDate":"2024-01-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139092224","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-01-04DOI: 10.35848/1347-4065/ad106d
Yuri Fujimoto, Shin-ichi Nishizawa, Wataru Saito
Surge voltage at insulated gate bipolar transistor turn-off switching was analyzed with dependence on cell design parameters. Although drift layer thinning is effective in improving trade-off characteristics between turn-off loss Eoff and on-state voltage Von, voltage surge is induced due to the quickly expanding depletion layer. Therefore, the surge voltage Vsurge has also a trade-off relationship with Von at the same Eoff condition. The origin of the voltage surge was analyzed using TCAD simulation, and the total amount of remaining holes in the drift layer during turn-off switching is a key factor for the Vsurge. A narrow mesa structure and thick buffer layer are effective for the improvement of trade-off characteristics between Vsurge and Von. However, the optimum buffer layer thickness depends on the voltage-class due to the speed for punch through.
分析了绝缘栅双极晶体管关断开关时的浪涌电压与电池设计参数的关系。虽然漂移层减薄能有效改善关断损耗 Eoff 和导通电压 Von 之间的权衡特性，但由于耗尽层迅速膨胀，会引起电压浪涌。因此，在相同的关断损耗条件下，浪涌电压 Vsurge 也与 Von 存在权衡关系。利用 TCAD 仿真分析了电压浪涌的起源，发现关断开关时漂移层中剩余孔的总量是影响 Vsurge 的关键因素。窄网格结构和厚缓冲层可有效改善 Vsurge 和 Von 之间的权衡特性。不过，最佳缓冲层厚度取决于电压等级，这是由击穿速度决定的。
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