Pub Date : 2024-08-28DOI: 10.35848/1347-4065/ad6b34
Ryosuke Sakata, Maiko Nagayoshi
The degradation acceleration based on dielectric thickness was evaluated by analyzing the local insulation degraded area in prototype Ni-BaTiO3 multilayer ceramic capacitors. Locally thinned dielectric layers, resulting from nickel internal electrode bulges, were associated with shorter lifetimes than the mean time to failure observed in highly accelerated life test. A strong correlation was observed between the minimum thickness of the dielectric layer at the degraded area and the lifetime. The electric field acceleration coefficient was derived from the correlation between the electric field strength, calculated from the dielectric thickness at the degraded area, and the lifetime. The impact of dielectric thinning on degradation acceleration was quantified by analyzing these local degraded areas. The factors influencing degradation acceleration were also discussed based on these findings.
{"title":"Quantitative evaluation of the degradation acceleration of insulation at local area in multilayer ceramic capacitors","authors":"Ryosuke Sakata, Maiko Nagayoshi","doi":"10.35848/1347-4065/ad6b34","DOIUrl":"https://doi.org/10.35848/1347-4065/ad6b34","url":null,"abstract":"The degradation acceleration based on dielectric thickness was evaluated by analyzing the local insulation degraded area in prototype Ni-BaTiO<sub>3</sub> multilayer ceramic capacitors. Locally thinned dielectric layers, resulting from nickel internal electrode bulges, were associated with shorter lifetimes than the mean time to failure observed in highly accelerated life test. A strong correlation was observed between the minimum thickness of the dielectric layer at the degraded area and the lifetime. The electric field acceleration coefficient was derived from the correlation between the electric field strength, calculated from the dielectric thickness at the degraded area, and the lifetime. The impact of dielectric thinning on degradation acceleration was quantified by analyzing these local degraded areas. The factors influencing degradation acceleration were also discussed based on these findings.","PeriodicalId":14741,"journal":{"name":"Japanese Journal of Applied Physics","volume":"11 1","pages":""},"PeriodicalIF":1.5,"publicationDate":"2024-08-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142218118","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}
Wurtzite-type ferroelectrics have attracted much attention as next-generation ferroelectric materials due to their high spontaneous polarizations since the first experimental demonstration of polarization switching for Sc-doped AlN. However, wurtzite-type ferroelectrics require high electric fields to switch their polarization direction, resulting in small margins with breakdown electric fields. To address this issue, considerable efforts have been made to explore wurtzite ferroelectrics with moderate switching barriers. In this study, our first-principles calculations have predicted the ferroelectricity of defective wurtzite α-Ga2S3. The calculated polarization is 60 μC cm−2, which is comparable to or smaller than those of conventional wurtzite ferroelectrics. The minimum energy pathway associated with polarization switching reveals a moderate switching barrier of 67 meV/atom. The energy landscape for α-Ga2S3 is quite different from that for its isostructural Al-based counterpart α-Al2S3, which our recent theoretical study has predicted to have quadruple-well ferroelectricity. The difference in chemical bonding between cations and sulfide ions accounts for their different energy landscapes for polarization switching.
{"title":"First-principles prediction of ferroelectricity in defective wurtzite α-Ga2S3","authors":"Yuto Shimomura, Katsuro Hayashi, Hirofumi Akamatsu","doi":"10.35848/1347-4065/ad6c59","DOIUrl":"https://doi.org/10.35848/1347-4065/ad6c59","url":null,"abstract":"Wurtzite-type ferroelectrics have attracted much attention as next-generation ferroelectric materials due to their high spontaneous polarizations since the first experimental demonstration of polarization switching for Sc-doped AlN. However, wurtzite-type ferroelectrics require high electric fields to switch their polarization direction, resulting in small margins with breakdown electric fields. To address this issue, considerable efforts have been made to explore wurtzite ferroelectrics with moderate switching barriers. In this study, our first-principles calculations have predicted the ferroelectricity of defective wurtzite <italic toggle=\"yes\">α</italic>-Ga<sub>2</sub>S<sub>3</sub>. The calculated polarization is 60 <italic toggle=\"yes\">μ</italic>C cm<sup>−2</sup>, which is comparable to or smaller than those of conventional wurtzite ferroelectrics. The minimum energy pathway associated with polarization switching reveals a moderate switching barrier of 67 meV/atom. The energy landscape for <italic toggle=\"yes\">α</italic>-Ga<sub>2</sub>S<sub>3</sub> is quite different from that for its isostructural Al-based counterpart <italic toggle=\"yes\">α</italic>-Al<sub>2</sub>S<sub>3</sub>, which our recent theoretical study has predicted to have quadruple-well ferroelectricity. The difference in chemical bonding between cations and sulfide ions accounts for their different energy landscapes for polarization switching.","PeriodicalId":14741,"journal":{"name":"Japanese Journal of Applied Physics","volume":"181 1","pages":""},"PeriodicalIF":1.5,"publicationDate":"2024-08-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142218122","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}
Chemically amplified resists (CARs) are widely used in lithography for manufacturing semiconductor devices. To reduce the occurrence of stochastic defects in CARs, increased acid generator concentration is required. In this study, we investigated the effects of acid generator anions on the radiation-induced decomposition of acid generators using electron pulse radiolysis and γ-radiolysis methods. Their effects on the dissolution dynamics of poly(4-hydroxystyrene) (PHS) films were also investigated using contact angle measurement and quartz crystal microbalance methods. Triphenylsulfonium trifluoromethanesulfonate, triphenylsulfonium nonafluoro-1-butanesulfonate, triphenylsulfonium 4-toluenesulfonate, and triphenylsulfonium salicylate, were used as acid generators or photodecomposable quenchers. The anions showed minimal effect on the decomposition of the acid generators and photodecomposable quenchers; however, they influenced the surface free energy, dissolution kinetics of the PHS films, and water penetration into the PHS films. In particular, the effect of salicylate on the dissolution kinetics of PHS films is significant.
化学放大抗蚀剂（CAR）被广泛应用于制造半导体器件的光刻技术中。为了减少 CAR 中随机缺陷的发生，需要提高酸发生器的浓度。在这项研究中，我们使用电子脉冲辐射分解法和γ-辐射分解法研究了酸发生器阴离子对辐射诱导的酸发生器分解的影响。我们还使用接触角测量法和石英晶体微天平法研究了它们对聚（4-羟基苯乙烯）（PHS）薄膜溶解动力学的影响。三苯基锍三氟甲烷磺酸盐、三苯基锍壬氟丁烷磺酸盐、三苯基锍 4-甲苯磺酸盐和三苯基锍水杨酸盐被用作酸生成物或光分解淬灭剂。阴离子对酸生成物和光分解淬灭剂的分解影响极小，但它们会影响 PHS 薄膜的表面自由能、溶解动力学以及水对 PHS 薄膜的渗透。其中，水杨酸盐对 PHS 薄膜溶解动力学的影响尤为显著。
{"title":"Effects of acid generator anions on radiation-induced decomposition and dissolution kinetics of chemically amplified resists","authors":"Yoshika Tsuda, Yusa Muroya, Takahiro Kozawa, Takuya Ikeda, Yoshitaka Komuro","doi":"10.35848/1347-4065/ad6b6a","DOIUrl":"https://doi.org/10.35848/1347-4065/ad6b6a","url":null,"abstract":"Chemically amplified resists (CARs) are widely used in lithography for manufacturing semiconductor devices. To reduce the occurrence of stochastic defects in CARs, increased acid generator concentration is required. In this study, we investigated the effects of acid generator anions on the radiation-induced decomposition of acid generators using electron pulse radiolysis and <italic toggle=\"yes\">γ</italic>-radiolysis methods. Their effects on the dissolution dynamics of poly(4-hydroxystyrene) (PHS) films were also investigated using contact angle measurement and quartz crystal microbalance methods. Triphenylsulfonium trifluoromethanesulfonate, triphenylsulfonium nonafluoro-1-butanesulfonate, triphenylsulfonium 4-toluenesulfonate, and triphenylsulfonium salicylate, were used as acid generators or photodecomposable quenchers. The anions showed minimal effect on the decomposition of the acid generators and photodecomposable quenchers; however, they influenced the surface free energy, dissolution kinetics of the PHS films, and water penetration into the PHS films. In particular, the effect of salicylate on the dissolution kinetics of PHS films is significant.","PeriodicalId":14741,"journal":{"name":"Japanese Journal of Applied Physics","volume":"29 1","pages":""},"PeriodicalIF":1.5,"publicationDate":"2024-08-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142218120","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 : 2024-08-27DOI: 10.35848/1347-4065/ad6b9f
Yasuaki Nakamura, Madoka Nishikawa, Simon J. Greaves, Yasushi Kanai, Yoshihiro Okamoto
Three-dimensional (3D) magnetic recording with multiple recording layers has garnered considerable attention as a next-generation magnetic recording method that uses dual conventional recording layers and a magnetoresistive (MR) head for reading. In this work, to examine signal processing methods for the 3D magnetic read/write (R/W) channel using heat-assisted magnetic recording (HAMR), we have constructed a HAMR R/W channel using a granular media model. Our 3D HAMR R/W channel model, specialized for signal processing development, can account for the Curie temperatures of the recording layers and the temperature distribution of the heat source.
{"title":"A study on HAMR read/write channel models for double layer magnetic recording","authors":"Yasuaki Nakamura, Madoka Nishikawa, Simon J. Greaves, Yasushi Kanai, Yoshihiro Okamoto","doi":"10.35848/1347-4065/ad6b9f","DOIUrl":"https://doi.org/10.35848/1347-4065/ad6b9f","url":null,"abstract":"Three-dimensional (3D) magnetic recording with multiple recording layers has garnered considerable attention as a next-generation magnetic recording method that uses dual conventional recording layers and a magnetoresistive (MR) head for reading. In this work, to examine signal processing methods for the 3D magnetic read/write (R/W) channel using heat-assisted magnetic recording (HAMR), we have constructed a HAMR R/W channel using a granular media model. Our 3D HAMR R/W channel model, specialized for signal processing development, can account for the Curie temperatures of the recording layers and the temperature distribution of the heat source.","PeriodicalId":14741,"journal":{"name":"Japanese Journal of Applied Physics","volume":"300 1","pages":""},"PeriodicalIF":1.5,"publicationDate":"2024-08-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142218121","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 : 2024-08-26DOI: 10.35848/1347-4065/ad6964
Xiaoling Chen, Yidi Bao, Chunxue Ji, Ye Li, Guiqiang Yang, Wen Liu, Qing Liu, Fuhua Yang, Xiaodong Wang
Surface defects seriously affect the electronic properties of the optoelectronic devices. In this paper, the surface defect analysis of GaAs thin-film solar cells grown by molecular beam epitaxy is carried out by a photon emission microscope. Two types of oval defects at the locations of the luminous spots are observed. The morphology and chemical composition analysis indicates that GaAs dust contamination on the wafer surface and excessive As clusters are the origins of oval defects. The electrical property analysis shows that oval defects in the epitaxial layer should be one of the important reasons for the nonideal leakage current of the GaAs thin-film solar cell.
{"title":"Photon emission microscope analysis on surface defects of GaAs thin-film solar cells grown by molecular beam epitaxy","authors":"Xiaoling Chen, Yidi Bao, Chunxue Ji, Ye Li, Guiqiang Yang, Wen Liu, Qing Liu, Fuhua Yang, Xiaodong Wang","doi":"10.35848/1347-4065/ad6964","DOIUrl":"https://doi.org/10.35848/1347-4065/ad6964","url":null,"abstract":"Surface defects seriously affect the electronic properties of the optoelectronic devices. In this paper, the surface defect analysis of GaAs thin-film solar cells grown by molecular beam epitaxy is carried out by a photon emission microscope. Two types of oval defects at the locations of the luminous spots are observed. The morphology and chemical composition analysis indicates that GaAs dust contamination on the wafer surface and excessive As clusters are the origins of oval defects. The electrical property analysis shows that oval defects in the epitaxial layer should be one of the important reasons for the nonideal leakage current of the GaAs thin-film solar cell.","PeriodicalId":14741,"journal":{"name":"Japanese Journal of Applied Physics","volume":"26 1","pages":""},"PeriodicalIF":1.5,"publicationDate":"2024-08-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142218123","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 paper, an N-type Lateral Diffused Metal Oxide Semiconductor (LDMOS) device was designed using a heavily doped P+ well and drain N-type buffer layer structure in the BCD process. The hardened mechanism of heavily doped P+ well and drain N-type buffer layer structures was simulated and analyzed using a TCAD device simulator. To verify the anti-SEE performance of the LDMOS, the irradiation test was conducted using Ta ion (LET = 79.2 MeV·cm−2 mg−1). The results show that increasing P+ well doping concentration and using buffer layer structure can increase the single event burnout (SEB) voltage of high-voltage LDMOS devices. SEB did not occur within the full operation voltage range.
本文采用 BCD 工艺设计了一种 N 型侧向扩散金属氧化物半导体 (LDMOS) 器件，该器件采用了重掺杂 P+ 井和漏极 N 型缓冲层结构。使用 TCAD 器件模拟器模拟和分析了重掺杂 P+ 井和漏极 N 型缓冲层结构的硬化机制。为了验证 LDMOS 的抗 SEE 性能，使用 Ta 离子（LET = 79.2 MeV-cm-2 mg-1）进行了辐照测试。结果表明，增加 P+ 孔掺杂浓度和使用缓冲层结构可以提高高压 LDMOS 器件的单次烧毁（SEB）电压。在全工作电压范围内，SEB 不会发生。
{"title":"Research on single event effects and hardening design of LDMOS transistors","authors":"Ying Wang, Wei Zhou, Ling Peng, Fei Chu, Zongmin Wang, Ying Kong, Guicai Hu, Yifan Hu","doi":"10.35848/1347-4065/ad6b6b","DOIUrl":"https://doi.org/10.35848/1347-4065/ad6b6b","url":null,"abstract":"In this paper, an N-type Lateral Diffused Metal Oxide Semiconductor (LDMOS) device was designed using a heavily doped P+ well and drain N-type buffer layer structure in the BCD process. The hardened mechanism of heavily doped P+ well and drain N-type buffer layer structures was simulated and analyzed using a TCAD device simulator. To verify the anti-SEE performance of the LDMOS, the irradiation test was conducted using Ta ion (LET = 79.2 MeV·cm<sup>−2</sup> mg<sup>−1</sup>). The results show that increasing P+ well doping concentration and using buffer layer structure can increase the single event burnout (SEB) voltage of high-voltage LDMOS devices. SEB did not occur within the full operation voltage range.","PeriodicalId":14741,"journal":{"name":"Japanese Journal of Applied Physics","volume":"23 1","pages":""},"PeriodicalIF":1.5,"publicationDate":"2024-08-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142218125","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 : 2024-08-23DOI: 10.35848/1347-4065/ad68f1
Jeail Kim, Hwihyeon Kang, Ugaitz Elu, Dasol Kim, Florian Haberstroh, Themistoklis Sidiropoulos, Tobias Steinle, Matthias Baudisch, Lisa Ortmann, Alexandra S. Landsman, Jens Biegert, Alexis Chacón, Dong Eon Kim
We propose the generation of a widely tunable UV-to-IR frequency comb by high-order sideband generation (HSB) spectrum emitted from semiconductors. In our theoretical simulations, we demonstrate the high-order sideband signals of two series (2mΩseed + (2n + 1)ωdriver, and (2m + 1)Ωseed + 2nωdriver), where m and n are integers of a seed pulse and a driver laser frequency, respectively. The simulations also reveal the intensity of HSB scale with the driver laser power, both perturbatively and non-perturbatively. We find that the harmonic position and spacing of the high-order sideband emission can be controlled by varying the seed pulse and driver photon energies. In the experiment, we applied a visible (ℏΩseed = 3.1 eV, ∼400 nm) seed pulse and mid-infrared (MIR, ℏωdriver = 0.4 eV, 3.1 μm) driver pulses to ZnSe target. Our experimental observations confirmed the UV (4.7 eV, 263 nm and 3.9 eV, 317 nm) HSB generation.
{"title":"Tunable UV ∼ IR frequency comb generation via high-order sideband generation","authors":"Jeail Kim, Hwihyeon Kang, Ugaitz Elu, Dasol Kim, Florian Haberstroh, Themistoklis Sidiropoulos, Tobias Steinle, Matthias Baudisch, Lisa Ortmann, Alexandra S. Landsman, Jens Biegert, Alexis Chacón, Dong Eon Kim","doi":"10.35848/1347-4065/ad68f1","DOIUrl":"https://doi.org/10.35848/1347-4065/ad68f1","url":null,"abstract":"We propose the generation of a widely tunable UV-to-IR frequency comb by high-order sideband generation (HSB) spectrum emitted from semiconductors. In our theoretical simulations, we demonstrate the high-order sideband signals of two series (2<italic toggle=\"yes\">m</italic>\u0000<inline-formula>\u0000<tex-math>\u0000<?CDATA ${{rm{Omega }}}_{mathrm{seed}}$?>\u0000</tex-math>\u0000<mml:math overflow=\"scroll\"><mml:msub><mml:mi mathvariant=\"normal\">Ω</mml:mi><mml:mi>seed</mml:mi></mml:msub></mml:math>\u0000<inline-graphic xlink:href=\"jjapad68f1ieqn1.gif\" xlink:type=\"simple\"></inline-graphic>\u0000</inline-formula> + (2<italic toggle=\"yes\">n</italic> + 1)<inline-formula>\u0000<tex-math>\u0000<?CDATA ${omega }_{mathrm{driver}},$?>\u0000</tex-math>\u0000<mml:math overflow=\"scroll\"><mml:msub><mml:mi>ω</mml:mi><mml:mi>driver</mml:mi></mml:msub><mml:mo>,</mml:mo></mml:math>\u0000<inline-graphic xlink:href=\"jjapad68f1ieqn2.gif\" xlink:type=\"simple\"></inline-graphic>\u0000</inline-formula> and (2<italic toggle=\"yes\">m</italic> + 1)<inline-formula>\u0000<tex-math>\u0000<?CDATA ${{rm{Omega }}}_{mathrm{seed}}$?>\u0000</tex-math>\u0000<mml:math overflow=\"scroll\"><mml:msub><mml:mi mathvariant=\"normal\">Ω</mml:mi><mml:mi>seed</mml:mi></mml:msub></mml:math>\u0000<inline-graphic xlink:href=\"jjapad68f1ieqn3.gif\" xlink:type=\"simple\"></inline-graphic>\u0000</inline-formula> + 2<inline-formula>\u0000<tex-math>\u0000<?CDATA $n{omega }_{mathrm{driver}}$?>\u0000</tex-math>\u0000<mml:math overflow=\"scroll\"><mml:mi>n</mml:mi><mml:msub><mml:mi>ω</mml:mi><mml:mi>driver</mml:mi></mml:msub></mml:math>\u0000<inline-graphic xlink:href=\"jjapad68f1ieqn4.gif\" xlink:type=\"simple\"></inline-graphic>\u0000</inline-formula>), where <italic toggle=\"yes\">m</italic> and <italic toggle=\"yes\">n</italic> are integers of a seed pulse and a driver laser frequency, respectively. The simulations also reveal the intensity of HSB scale with the driver laser power, both perturbatively and non-perturbatively. We find that the harmonic position and spacing of the high-order sideband emission can be controlled by varying the seed pulse and driver photon energies. In the experiment, we applied a visible (<inline-formula>\u0000<tex-math>\u0000<?CDATA ${rm{hslash }}{{rm{Omega }}}_{mathrm{seed}}$?>\u0000</tex-math>\u0000<mml:math overflow=\"scroll\"><mml:mi mathvariant=\"normal\">ℏ</mml:mi><mml:msub><mml:mi mathvariant=\"normal\">Ω</mml:mi><mml:mi>seed</mml:mi></mml:msub></mml:math>\u0000<inline-graphic xlink:href=\"jjapad68f1ieqn5.gif\" xlink:type=\"simple\"></inline-graphic>\u0000</inline-formula> = 3.1 eV, ∼400 nm) seed pulse and mid-infrared (MIR, <inline-formula>\u0000<tex-math>\u0000<?CDATA ${{rm{hslash }}omega }_{mathrm{driver}}$?>\u0000</tex-math>\u0000<mml:math overflow=\"scroll\"><mml:msub><mml:mrow><mml:mi mathvariant=\"normal\">ℏ</mml:mi><mml:mi>ω</mml:mi></mml:mrow><mml:mi>driver</mml:mi></mml:msub></mml:math>\u0000<inline-graphic xlink:href=\"jjapad68f1ieqn6.gif\" xlink:type=\"simple\"></inline-graphic>\u0000</inline-formula> = 0.4 eV, 3.1 μm) driver pulses to ZnSe target. Our experimental observations confirmed the UV (4.7 eV, 263 nm and 3.9 eV, 317 nm) HSB generation.","PeriodicalId":14741,"journal":{"name":"Japanese Journal of Applied Physics","volume":"70 1","pages":""},"PeriodicalIF":1.5,"publicationDate":"2024-08-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142218124","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}
Water adsorbed on carbon nanotube (CNT) surfaces is known to have unique properties, however, the structure and dynamics of adsorbed water on CNT have been unclarified. We investigated the temperature dependence of the structure and rotational dynamics of adsorbed water on carbon nanotube surfaces using a classical molecular dynamics simulation. At a specific adsorption amount and temperature, a rhombic ice structure and a polygon structure that includes pentamers and hexamers coexist in the adsorbed water. Rotational dynamics analysis indicates that the rhombic ice exhibits solid-like behavior and that the polygon structure exhibits liquid-like behavior. Their coexistence is regarded as a solid–liquid crossover.
{"title":"Structure and dynamics of adsorbed water on carbon nanotubes: a molecular dynamics simulation","authors":"Yuki Maekawa, Yusei Kioka, Kenji Sasaoka, Yoshikazu Homma, Takahiro Yamamoto","doi":"10.35848/1347-4065/ad6abd","DOIUrl":"https://doi.org/10.35848/1347-4065/ad6abd","url":null,"abstract":"Water adsorbed on carbon nanotube (CNT) surfaces is known to have unique properties, however, the structure and dynamics of adsorbed water on CNT have been unclarified. We investigated the temperature dependence of the structure and rotational dynamics of adsorbed water on carbon nanotube surfaces using a classical molecular dynamics simulation. At a specific adsorption amount and temperature, a rhombic ice structure and a polygon structure that includes pentamers and hexamers coexist in the adsorbed water. Rotational dynamics analysis indicates that the rhombic ice exhibits solid-like behavior and that the polygon structure exhibits liquid-like behavior. Their coexistence is regarded as a solid–liquid crossover.","PeriodicalId":14741,"journal":{"name":"Japanese Journal of Applied Physics","volume":"58 1","pages":""},"PeriodicalIF":1.5,"publicationDate":"2024-08-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142218129","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 : 2024-08-21DOI: 10.35848/1347-4065/ad6abe
Keigo Bito, Masaki Ishiguro, Hadirah A. Radzuan, Hikaru Hiroshige, Tomohiro Motoyama, Yusui Nakamura, Joel T. Asubar, Zenji Yatabe
Uniform thickness Al2O3 thin films have been deposited by eco-friendly mist CVD. The obtained Al2O3 film has an optical band gap value of more than 6.5 eV and a refractive index of 1.64 at 633 nm. The combination of capacitance–voltage (C–V) fitting method with non-linear least-squares algorithm, frequency dispersion, photo-assisted, and proposed reverse bias-assisted C–V methods revealed interface state densities ranging from 1 × 1012 to 3 × 1013 cm−2eV−1 along the mist-Al2O3/AlGaN interface. These values are comparable to those reported for atomic layer deposited Al2O3 thin films.
{"title":"Interface state density in mist chemical vapor deposited Al2O3/AlGaN/GaN structure","authors":"Keigo Bito, Masaki Ishiguro, Hadirah A. Radzuan, Hikaru Hiroshige, Tomohiro Motoyama, Yusui Nakamura, Joel T. Asubar, Zenji Yatabe","doi":"10.35848/1347-4065/ad6abe","DOIUrl":"https://doi.org/10.35848/1347-4065/ad6abe","url":null,"abstract":"Uniform thickness Al<sub>2</sub>O<sub>3</sub> thin films have been deposited by eco-friendly mist CVD. The obtained Al<sub>2</sub>O<sub>3</sub> film has an optical band gap value of more than 6.5 eV and a refractive index of 1.64 at 633 nm. The combination of capacitance–voltage (<italic toggle=\"yes\">C</italic>–<italic toggle=\"yes\">V</italic>) fitting method with non-linear least-squares algorithm, frequency dispersion, photo-assisted, and proposed reverse bias-assisted <italic toggle=\"yes\">C</italic>–<italic toggle=\"yes\">V</italic> methods revealed interface state densities ranging from 1 × 10<sup>12</sup> to 3 × 10<sup>13</sup> cm<sup>−2</sup>eV<sup>−1</sup> along the mist-Al<sub>2</sub>O<sub>3</sub>/AlGaN interface. These values are comparable to those reported for atomic layer deposited Al<sub>2</sub>O<sub>3</sub> thin films.","PeriodicalId":14741,"journal":{"name":"Japanese Journal of Applied Physics","volume":"4 1","pages":""},"PeriodicalIF":1.5,"publicationDate":"2024-08-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142218182","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 Ba0.8Sr0.2Ti1−2xGaxNbxO3 (0 ≤ x ≤ 0.10) ceramics were fabricated and the electrical properties were evaluated regarding DC-bias and temperature characteristics of the dielectric properties. The ceramics with x = 0.10 exhibited a stable dielectric constant with a change of–40% within 25 °C–150 °C. The dielectric loss of all the co-doped ceramics was below 2% within 25 °C–200 °C. The Ba0.8Sr0.2Ti1−2xGaxNbxO3 ceramics showed a higher dielectric constant with a lower DC-bias dependence as compared to previous study on co-doped BaTiO3 ceramics. The Ba0.8Sr0.2Ti0.20Ga0.10Nb0.10O3 ceramics exhibited the best results of DC-bias dependence ≈−24%, dielectric constant at 100 kV cm−1 ≈ 560, and the dielectric constant at 0 kV cm−1 ≈ 735. The better results for the Ga–Nb co-doped BST ceramics might be due to the higher contribution of the ionic polarization in the BST base matrix resulting in a shallower potential energy curve.
{"title":"Investigation of Ga–Nb co-doped barium strontium titanate ceramics for DC-bias free dielectrics","authors":"Piyush Sapkota, Keito Yagasaki, Ichiro Fujii, Shintaro Ueno, Satoshi Wada","doi":"10.35848/1347-4065/ad690c","DOIUrl":"https://doi.org/10.35848/1347-4065/ad690c","url":null,"abstract":"The Ba<sub>0.8</sub>Sr<sub>0.2</sub>Ti<sub>1−2<italic toggle=\"yes\">x</italic>\u0000</sub>Ga<sub>\u0000<italic toggle=\"yes\">x</italic>\u0000</sub>Nb<sub>\u0000<italic toggle=\"yes\">x</italic>\u0000</sub>O<sub>3</sub> (0 ≤ <italic toggle=\"yes\">x</italic> ≤ 0.10) ceramics were fabricated and the electrical properties were evaluated regarding DC-bias and temperature characteristics of the dielectric properties. The ceramics with <italic toggle=\"yes\">x</italic> = 0.10 exhibited a stable dielectric constant with a change of–40% within 25 °C–150 °C. The dielectric loss of all the co-doped ceramics was below 2% within 25 °C–200 °C. The Ba<sub>0.8</sub>Sr<sub>0.2</sub>Ti<sub>1−2<italic toggle=\"yes\">x</italic>\u0000</sub>Ga<sub>\u0000<italic toggle=\"yes\">x</italic>\u0000</sub>Nb<sub>\u0000<italic toggle=\"yes\">x</italic>\u0000</sub>O<sub>3</sub> ceramics showed a higher dielectric constant with a lower DC-bias dependence as compared to previous study on co-doped BaTiO<sub>3</sub> ceramics. The Ba<sub>0.8</sub>Sr<sub>0.2</sub>Ti<sub>0.20</sub>Ga<sub>0.10</sub>Nb<sub>0.10</sub>O<sub>3</sub> ceramics exhibited the best results of DC-bias dependence ≈−24%, dielectric constant at 100 kV cm<sup>−1</sup> ≈ 560, and the dielectric constant at 0 kV cm<sup>−1</sup> ≈ 735. The better results for the Ga–Nb co-doped BST ceramics might be due to the higher contribution of the ionic polarization in the BST base matrix resulting in a shallower potential energy curve.","PeriodicalId":14741,"journal":{"name":"Japanese Journal of Applied Physics","volume":"37 1","pages":""},"PeriodicalIF":1.5,"publicationDate":"2024-08-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142218127","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}
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