Pub Date : 2024-08-09DOI: 10.35848/1347-4065/ad6dc1
Takumi Kato, Daiki Shiratori, Akito Watanabe, Y. Fujimoto, K. Asai, A. Nishikawa, Kai Okazaki, D. Nakauchi, N. Kawaguchi, Takayuki Yanagida
CsPbBr3 quantum dots-embedded SiO2 glasses were synthesized by the spark plasma sintering method as novel scintillators for γ-ray detectors. Their optical and scintillation properties were investigated to examine the scintillation performance. The XRD patterns observed a halo peak of the SiO2 glass phase and diffraction peaks of CsPbBr3. An emission peak due to CsPbBr3 quantum dots was detected at around 515 nm in both PL and scintillation spectra. The PL and scintillation decay time curves included a component of nanosecond order, resulting from CsPbBr3 quantum dots. Under γ-ray irradiation from 137Cs, the LY of the 0.2% CsPbBr3-embedded SiO2 glass was 150 photons/MeV.
{"title":"Scintillator application of CsPbBr3 quantum dots-embedded SiO2 glasses","authors":"Takumi Kato, Daiki Shiratori, Akito Watanabe, Y. Fujimoto, K. Asai, A. Nishikawa, Kai Okazaki, D. Nakauchi, N. Kawaguchi, Takayuki Yanagida","doi":"10.35848/1347-4065/ad6dc1","DOIUrl":"https://doi.org/10.35848/1347-4065/ad6dc1","url":null,"abstract":"\u0000 CsPbBr3 quantum dots-embedded SiO2 glasses were synthesized by the spark plasma sintering method as novel scintillators for γ-ray detectors. Their optical and scintillation properties were investigated to examine the scintillation performance. The XRD patterns observed a halo peak of the SiO2 glass phase and diffraction peaks of CsPbBr3. An emission peak due to CsPbBr3 quantum dots was detected at around 515 nm in both PL and scintillation spectra. The PL and scintillation decay time curves included a component of nanosecond order, resulting from CsPbBr3 quantum dots. Under γ-ray irradiation from 137Cs, the LY of the 0.2% CsPbBr3-embedded SiO2 glass was 150 photons/MeV.","PeriodicalId":505044,"journal":{"name":"Japanese Journal of Applied Physics","volume":"51 2","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-08-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141922699","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The etching mechanism of silicon nitride (Si3N4) film depending on peak-to-peak bias voltage (V pp) in Ar/CH2F2/O2 gas-mixture plasmas for high-aspect-ratio etching process was investigated. It was observed that the Si3N4-film etch rate initially decreased with increase in the V pp up to 3630 V, but then increased beyond this threshold. This unusual etching behavior can be attributed to the formation of a modified layer on the surface of the Si3N4 film. The characteristics of the modified layer, such as thickness and atomic composition, were found to be strongly influenced by the ion energy and gas chemistry of the process conditions.
{"title":"Influence of bias voltage on the Ar/CH2F2/O2 plasma etching of Si3N4 films","authors":"Shuichi Kuboi, Junji Kataoka, Daiki Iino, Kazuaki Kurihara, Hirotaka Toyoda, Hiroyuki Fukumizu","doi":"10.35848/1347-4065/ad6d20","DOIUrl":"https://doi.org/10.35848/1347-4065/ad6d20","url":null,"abstract":"\u0000 The etching mechanism of silicon nitride (Si3N4) film depending on peak-to-peak bias voltage (V\u0000 pp) in Ar/CH2F2/O2 gas-mixture plasmas for high-aspect-ratio etching process was investigated. It was observed that the Si3N4-film etch rate initially decreased with increase in the V\u0000 pp up to 3630 V, but then increased beyond this threshold. This unusual etching behavior can be attributed to the formation of a modified layer on the surface of the Si3N4 film. The characteristics of the modified layer, such as thickness and atomic composition, were found to be strongly influenced by the ion energy and gas chemistry of the process conditions.","PeriodicalId":505044,"journal":{"name":"Japanese Journal of Applied Physics","volume":"51 15","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-08-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141929599","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-07-26DOI: 10.35848/1347-4065/ad67e9
Nozomi Sato, Wensheng Wang, T. Eshita, Mitsuaki Oikawa, Masaaki Nakabayashi, K. Takai, Ko Nakamura, Kouichi Nagai, S. Mihara, Y. Hikosaka, H. Saito
We successfully developed highly {111} oriented metal-organic chemical vapor deposition (MOCVD) Pb(Zr,Ti)O3 (PZT) using IrOx/Ir instead of Ir as a bottom electrode. The {111} PZT orientation strongly depends on the IrOx thickness and the O2 content of the atmosphere (PO2) during IrOx deposition. The Ir surface easily oxidizes during PZT deposition and becomes rough, which results in poor {111} orientation of PZT. IrOx prevents the Ir surface from oxidizing and eventually changes Ir metal by O2 reduction after completing PZT deposition. We can obtain highly {111} oriented PZT by optimizing the IrOx thickness and PO2.
我们使用 IrOx/Ir 代替 Ir 作为底电极，成功研制出了高度{111}取向的金属有机化学气相沉积（MOCVD）Pb(Zr,Ti)O3 (PZT)。在 IrOx 沉积过程中，{111} PZT 的取向在很大程度上取决于 IrOx 的厚度和大气中的氧气含量（PO2）。在 PZT 沉积过程中，Ir 表面很容易氧化并变得粗糙，从而导致 PZT 的{111}取向不良。IrOx 可防止 Ir 表面氧化，并在完成 PZT 沉积后通过氧气还原最终改变 Ir 金属。通过优化 IrOx 厚度和 PO2，我们可以获得高度{111}取向的 PZT。
{"title":"Development of a Pb(Zr,Ti)O3 capacitor employing an IrOx/Ir bottom electrode for highly reliable ferroelectric random access memories","authors":"Nozomi Sato, Wensheng Wang, T. Eshita, Mitsuaki Oikawa, Masaaki Nakabayashi, K. Takai, Ko Nakamura, Kouichi Nagai, S. Mihara, Y. Hikosaka, H. Saito","doi":"10.35848/1347-4065/ad67e9","DOIUrl":"https://doi.org/10.35848/1347-4065/ad67e9","url":null,"abstract":"\u0000 We successfully developed highly {111} oriented metal-organic chemical vapor deposition (MOCVD) Pb(Zr,Ti)O3 (PZT) using IrOx/Ir instead of Ir as a bottom electrode. The {111} PZT orientation strongly depends on the IrOx thickness and the O2 content of the atmosphere (PO2) during IrOx deposition. The Ir surface easily oxidizes during PZT deposition and becomes rough, which results in poor {111} orientation of PZT. IrOx prevents the Ir surface from oxidizing and eventually changes Ir metal by O2 reduction after completing PZT deposition. We can obtain highly {111} oriented PZT by optimizing the IrOx thickness and PO2.","PeriodicalId":505044,"journal":{"name":"Japanese Journal of Applied Physics","volume":"55 31","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-07-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141799923","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-07-26DOI: 10.35848/1347-4065/ad6813
Ryo Tabata, Moeka Oosumi, Ryosuke Matsubara, A. Kubono
Conformal coatings are crucial for various applications. In this study, we investigate polyurea coatings on complex-shape polytetrafluoroethylene (PTFE) membranes using vapor deposition polymerization. The diffusion mechanism involves monomer adsorption and desorption on PTFE fibers, enhanced by an increased substrate temperature, facilitating monomer diffusion. A system pressure of 100 Pa promoted monomer collisions, forming oligomers with lower desorption rates, aiding polymer thin-film formation. The combination of high substrate temperature for diffusion and gas-phase oligomer formation resulted in uniform polyurea coatings across the PTFE membrane. A non-exhaustion method provided an extensive monomer diffusion, achieving a thorough polyurea deposition throughout the membrane structure.
保形涂层对于各种应用都至关重要。在本研究中，我们利用气相沉积聚合法研究了复杂形状聚四氟乙烯（PTFE）膜上的聚脲涂层。扩散机制包括单体在聚四氟乙烯纤维上的吸附和解吸，基底温度的升高促进了单体的扩散。100 Pa 的系统压力促进了单体碰撞，形成了解吸率较低的低聚物，有助于聚合物薄膜的形成。扩散基底温度高和气相低聚物形成相结合，在聚四氟乙烯膜上形成了均匀的聚脲涂层。非排气法提供了广泛的单体扩散，实现了整个膜结构中聚脲的彻底沉积。
{"title":"Monomer diffusion tendencies in complex-shaped materials by vapor deposition polymerization","authors":"Ryo Tabata, Moeka Oosumi, Ryosuke Matsubara, A. Kubono","doi":"10.35848/1347-4065/ad6813","DOIUrl":"https://doi.org/10.35848/1347-4065/ad6813","url":null,"abstract":"\u0000 Conformal coatings are crucial for various applications. In this study, we investigate polyurea coatings on complex-shape polytetrafluoroethylene (PTFE) membranes using vapor deposition polymerization. The diffusion mechanism involves monomer adsorption and desorption on PTFE fibers, enhanced by an increased substrate temperature, facilitating monomer diffusion. A system pressure of 100 Pa promoted monomer collisions, forming oligomers with lower desorption rates, aiding polymer thin-film formation. The combination of high substrate temperature for diffusion and gas-phase oligomer formation resulted in uniform polyurea coatings across the PTFE membrane. A non-exhaustion method provided an extensive monomer diffusion, achieving a thorough polyurea deposition throughout the membrane structure.","PeriodicalId":505044,"journal":{"name":"Japanese Journal of Applied Physics","volume":"35 22","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-07-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141800593","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-07-25DOI: 10.35848/1347-4065/ad679a
S. Takyu, K. Matsumoto, Tetsuya Hirade, F. Nishikido, G. Akamatsu, H. Tashima, M. Takahashi, Taiga Yamaya
Positrons and electrons sometimes exist as the unstable species positronium (Ps) in living organisms. The time it takes for Ps to annihilate represents the Ps lifetime and it varies depending on the surrounding electron density. The Ps lifetime may add new biological information to PET scan information. To discuss the feasibility of quantifying (free) radicals in vivo by the Ps lifetime, we used a clinical PET system to make Ps lifetime measurements in aqueous solutions containing radicals. The results suggested that differences in radical concentrations in aqueous solutions of the order of a few mM could be quantified by the Ps lifetime if the counting statistic of the time difference spectra was more than 108 events. This concentration was much higher than the radical concentration generated in the physiological functions of living organisms. We concluded that quantification of radicals generated in vivo by using the Ps lifetime is practically hopeless.
在生物体内，正电子和电子有时会以不稳定种类正电子（Ps）的形式存在。正电子湮灭所需的时间即为正电子寿命，它随周围电子密度的不同而变化。Ps 寿命可为 PET 扫描信息增添新的生物信息。为了讨论用 Ps 寿命量化体内（自由）自由基的可行性，我们使用临床 PET 系统对含有自由基的水溶液进行了 Ps 寿命测量。结果表明，如果时差光谱的计数统计量超过 108 个事件，则水溶液中几毫微米数量级的自由基浓度差异可通过 Ps 寿命进行量化。这一浓度远远高于生物体生理功能中产生的自由基浓度。我们的结论是，利用 Ps 寿命对体内产生的自由基进行量化实际上是没有希望的。
{"title":"Quantification of radicals in aqueous solution by positronium lifetime: an experiment using a clinical PET scanner","authors":"S. Takyu, K. Matsumoto, Tetsuya Hirade, F. Nishikido, G. Akamatsu, H. Tashima, M. Takahashi, Taiga Yamaya","doi":"10.35848/1347-4065/ad679a","DOIUrl":"https://doi.org/10.35848/1347-4065/ad679a","url":null,"abstract":"\u0000 Positrons and electrons sometimes exist as the unstable species positronium (Ps) in living organisms. The time it takes for Ps to annihilate represents the Ps lifetime and it varies depending on the surrounding electron density. The Ps lifetime may add new biological information to PET scan information. To discuss the feasibility of quantifying (free) radicals in vivo by the Ps lifetime, we used a clinical PET system to make Ps lifetime measurements in aqueous solutions containing radicals. The results suggested that differences in radical concentrations in aqueous solutions of the order of a few mM could be quantified by the Ps lifetime if the counting statistic of the time difference spectra was more than 108 events. This concentration was much higher than the radical concentration generated in the physiological functions of living organisms. We concluded that quantification of radicals generated in vivo by using the Ps lifetime is practically hopeless.","PeriodicalId":505044,"journal":{"name":"Japanese Journal of Applied Physics","volume":"28 11","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-07-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141805033","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
In this work, high-performance negative differential resistance (NDR) characteristics are demonstrated in homoepitaxial AlN/GaN double-barrier resonant tunneling diodes (RTDs). The devices are grown by plasma-assisted molecular beam epitaxy on bulk GaN substrates and exhibit robust and repeatable NDR at room-temperature. High peak current density of 183 kA/cm2 is simultaneously demonstrated with a large peak-to-valley current ratio of 2.07, mainly benefiting from the significantly reduced dislocation density and improved hyper-abrupt heterointerfaces in the active region, which boosts the electron quantum transport in the resonant tunneling cavity. The achievement shows the promising potential to enhance the oscillation frequency and output power of GaN-based RTD oscillator, an imperative for next generation high-power solid-state compact terahertz oscillators application.
{"title":"High-performance negative differential resistance characteristics in homoepitaxial AlN/GaN double-barrier resonant tunneling diodes","authors":"Fang Liu, J. Xue, zumao li, guanlin wu, JiaJia Yao, jinyuan yuan, RenJie Liu, cheng zhao, wenbo sun, Kai Zhang, Jincheng Zhang, Yue Hao","doi":"10.35848/1347-4065/ad679b","DOIUrl":"https://doi.org/10.35848/1347-4065/ad679b","url":null,"abstract":"\u0000 In this work, high-performance negative differential resistance (NDR) characteristics are demonstrated in homoepitaxial AlN/GaN double-barrier resonant tunneling diodes (RTDs). The devices are grown by plasma-assisted molecular beam epitaxy on bulk GaN substrates and exhibit robust and repeatable NDR at room-temperature. High peak current density of 183 kA/cm2 is simultaneously demonstrated with a large peak-to-valley current ratio of 2.07, mainly benefiting from the significantly reduced dislocation density and improved hyper-abrupt heterointerfaces in the active region, which boosts the electron quantum transport in the resonant tunneling cavity. The achievement shows the promising potential to enhance the oscillation frequency and output power of GaN-based RTD oscillator, an imperative for next generation high-power solid-state compact terahertz oscillators application.","PeriodicalId":505044,"journal":{"name":"Japanese Journal of Applied Physics","volume":"7 5","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-07-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141803296","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-07-25DOI: 10.35848/1347-4065/ad6776
Takashi Nunokawa, Kenji Takashima, Kotaro Mizuno, Clive A. Randall
Cold Sintering Process is capable of densifying ceramics and metal powders with other phases into composite materials without inducing chemical reactions between the constituent phases or causing decomposition of any phases. In this study, we considered the co-sintering of BaTiO3 powders with polytetrafluoroethylene (PTFE) in the grain boundaries. We examined microstructure and dielectric properties of these composites with different volume fractions of PTFE. The composites were highly dispersive from microstructure and general mixing laws, due to using fine PTFE. Transmission electron microscopy studies demonstrated that the thickness of the PTFE in the grain boundaries was determined with different volume fractions of PTFE. The cold-sintered BaTiO3 composites had high volume resistivity (>1011 Ω·cm), enhancing the resistivity of the cold-sintered pure BaTiO3 using Ba(OH)2･8H2O transient phase. Reliability tests, such as breakdown strength and J-t curves, were conducted, the reliability improved by using fine powders of PTFE with controlled mixing.
{"title":"Dielectric properties and microstructure of BaTiO3-PTFE composites via cold sintering process","authors":"Takashi Nunokawa, Kenji Takashima, Kotaro Mizuno, Clive A. Randall","doi":"10.35848/1347-4065/ad6776","DOIUrl":"https://doi.org/10.35848/1347-4065/ad6776","url":null,"abstract":"\u0000 Cold Sintering Process is capable of densifying ceramics and metal powders with other phases into composite materials without inducing chemical reactions between the constituent phases or causing decomposition of any phases. In this study, we considered the co-sintering of BaTiO3 powders with polytetrafluoroethylene (PTFE) in the grain boundaries. We examined microstructure and dielectric properties of these composites with different volume fractions of PTFE. The composites were highly dispersive from microstructure and general mixing laws, due to using fine PTFE. Transmission electron microscopy studies demonstrated that the thickness of the PTFE in the grain boundaries was determined with different volume fractions of PTFE. The cold-sintered BaTiO3 composites had high volume resistivity (>1011 Ω·cm), enhancing the resistivity of the cold-sintered pure BaTiO3 using Ba(OH)2･8H2O transient phase. Reliability tests, such as breakdown strength and J-t curves, were conducted, the reliability improved by using fine powders of PTFE with controlled mixing.","PeriodicalId":505044,"journal":{"name":"Japanese Journal of Applied Physics","volume":"43 9","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-07-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141803873","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-07-24DOI: 10.35848/1347-4065/ad66da
Lei Meng, Xueyou Yuan, Junjie Gao, Wenkai Liu, Xiao-Guang Yang, T. Zhai, T. Yamada
Widegap ZnMgO thin films hold great potential for applications to high-efficiency generation of deep ultraviolet laser via frequency conversion, because of low light propagation loss and reversible polarization. In this work, we studied the effect of Li concentration on the second harmonic generation (SHG) of a-axis oriented ZnMgO thin films with an optical bandgap of about 3.96 eV. The SHG intensity per unit thickness from the ZnMgO thin film with a small Li concentration is approximately 10.7 times larger than the one without Li incorporation. The Li incorporation obviously enlarges interplanar spacing of (11-20) plane and reduces leakage current by 3 orders of magnitude. X-ray photoelectron spectroscopy measurements suggest the Li incorporation enhances SHG via enhancing electronic polarization. These findings uncover defect complexes based on Li interstitials in oxygen octahedron play a very important role in enhancing the nonlinear polarization of widegap ZnMgO thin films under optical frequency electric field.
宽带隙氧化锌（ZnMgO）薄膜具有低光传播损耗和可逆偏振的特点，在通过频率转换产生高效深紫外激光方面具有巨大的应用潜力。在这项工作中，我们研究了锂浓度对光带隙约为 3.96 eV 的 a 轴取向 ZnMgO 薄膜二次谐波发生（SHG）的影响。掺入少量锂的 ZnMgO 薄膜的单位厚度 SHG 强度大约是未掺入锂的薄膜的 10.7 倍。锂的加入明显扩大了（11-20）面的平面间距，并将漏电流降低了 3 个数量级。X 射线光电子能谱测量结果表明，锂的加入通过增强电子极化来提高 SHG。这些发现揭示了氧八面体中基于锂间隙的缺陷配合物在光频电场下增强宽隙 ZnMgO 薄膜的非线性极化方面起着非常重要的作用。
{"title":"Effect of Li concentration on second harmonic generation from widegap ZnMgO thin films","authors":"Lei Meng, Xueyou Yuan, Junjie Gao, Wenkai Liu, Xiao-Guang Yang, T. Zhai, T. Yamada","doi":"10.35848/1347-4065/ad66da","DOIUrl":"https://doi.org/10.35848/1347-4065/ad66da","url":null,"abstract":"\u0000 Widegap ZnMgO thin films hold great potential for applications to high-efficiency generation of deep ultraviolet laser via frequency conversion, because of low light propagation loss and reversible polarization. In this work, we studied the effect of Li concentration on the second harmonic generation (SHG) of a-axis oriented ZnMgO thin films with an optical bandgap of about 3.96 eV. The SHG intensity per unit thickness from the ZnMgO thin film with a small Li concentration is approximately 10.7 times larger than the one without Li incorporation. The Li incorporation obviously enlarges interplanar spacing of (11-20) plane and reduces leakage current by 3 orders of magnitude. X-ray photoelectron spectroscopy measurements suggest the Li incorporation enhances SHG via enhancing electronic polarization. These findings uncover defect complexes based on Li interstitials in oxygen octahedron play a very important role in enhancing the nonlinear polarization of widegap ZnMgO thin films under optical frequency electric field.","PeriodicalId":505044,"journal":{"name":"Japanese Journal of Applied Physics","volume":"43 8","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-07-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141808268","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-07-24DOI: 10.35848/1347-4065/ad66d9
Kodai Kikuchi, Kazunori Takahashi
An electron current is extracted from a 40.68 MHz inductively coupled plasma source, in which a grounded ion collector electrode is installed to maintain the charge neutrality, by applying a positive voltage to a metallic plate located downstream of the source. The ion collector has an exit orifice of either 20 mm or 2.2 mm in diameter, showing a larger electron extraction current for the 2.2-mm-diameter case. The result is discussed with a global model, implying a higher plasma density for the 2.2-mm-diameter case due to the increased neutral pressure in the source. Metallic and insulator exit having the 2.2-mm-diameter orifice are tested, providing a larger electron extraction current for the metallic case despite a small fraction of a change in the total ion collection area. It is speculated that the electron extraction current is affected by the ion collection near the electron extraction hole and the potential distribution.
{"title":"Characterization of electron extraction from a 40.68 MHz radiofrequency inductive plasma source","authors":"Kodai Kikuchi, Kazunori Takahashi","doi":"10.35848/1347-4065/ad66d9","DOIUrl":"https://doi.org/10.35848/1347-4065/ad66d9","url":null,"abstract":"\u0000 An electron current is extracted from a 40.68 MHz inductively coupled plasma source, in which a grounded ion collector electrode is installed to maintain the charge neutrality, by applying a positive voltage to a metallic plate located downstream of the source. The ion collector has an exit orifice of either 20 mm or 2.2 mm in diameter, showing a larger electron extraction current for the 2.2-mm-diameter case. The result is discussed with a global model, implying a higher plasma density for the 2.2-mm-diameter case due to the increased neutral pressure in the source. Metallic and insulator exit having the 2.2-mm-diameter orifice are tested, providing a larger electron extraction current for the metallic case despite a small fraction of a change in the total ion collection area. It is speculated that the electron extraction current is affected by the ion collection near the electron extraction hole and the potential distribution.","PeriodicalId":505044,"journal":{"name":"Japanese Journal of Applied Physics","volume":"87 4","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-07-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141807825","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-07-24DOI: 10.35848/1347-4065/ad66d7
Clint Eldrick Rey Petilla, Catherine Joy Dela Cruz, C. L. Mahinay
This study investigated the mechanical properties (elastic modulus, tensile strength, yield strength, and toughness) of different percent C of Silicon Carbide (SiC) using molecular dynamics simulations via the Large-scale Atomic/Molecular Massively Parallel Simulator (LAMMPS) with the uniaxial tensile test at four strain rates: 0.1, 0.5, 1.0, and 5.0 m/s, using the Tersoff potential. The simulation uses 20×20×20 atoms (108.6Å×108.6Å×108.6Å) of diamond cubic structure of Si, then carbon atoms were placed randomly at 5% intervals from 0-50 percent C. Results show improved mechanical properties when increasing percent C until peaking at 25%, before decreasing. This is caused by the shortest bond length at 25 percent C from the increase of Si=C using the Radial Distribution Function analysis. Increasing the strain rate generally improves the mechanical properties of the material. The deformation mechanism shows that increasing (decreasing) strain rate generally results in multiple (lesser) failure points with a ductile (brittle) fracture mode.
本研究通过大规模原子/分子大规模并行模拟器（LAMMPS）进行分子动力学模拟，在四种应变速率下进行单轴拉伸试验，研究了不同百分比 C 的碳化硅（SiC）的机械性能（弹性模量、拉伸强度、屈服强度和韧性）：0.1、0.5、1.0 和 5.0 m/s。模拟使用了 20×20×20 个原子（108.6 Å×108.6Å×108.6Å）的硅金刚石立方结构，然后在 0-50% C 之间以 5%的间隔随机放置碳原子。这是由于使用径向分布函数分析，Si=C 的增加使 25% C 时的键长最短。提高应变速率通常会改善材料的机械性能。变形机理表明，应变速率的增加（减小）通常会导致多个（较少）具有韧性（脆性）断裂模式的失效点。
{"title":"Mechanical properties of Si(1-x)-C(x): strength and stiffness of materials using LAMMPS molecular dynamics simulation","authors":"Clint Eldrick Rey Petilla, Catherine Joy Dela Cruz, C. L. Mahinay","doi":"10.35848/1347-4065/ad66d7","DOIUrl":"https://doi.org/10.35848/1347-4065/ad66d7","url":null,"abstract":"\u0000 This study investigated the mechanical properties (elastic modulus, tensile strength, yield strength, and toughness) of different percent C of Silicon Carbide (SiC) using molecular dynamics simulations via the Large-scale Atomic/Molecular Massively Parallel Simulator (LAMMPS) with the uniaxial tensile test at four strain rates: 0.1, 0.5, 1.0, and 5.0 m/s, using the Tersoff potential. The simulation uses 20×20×20 atoms (108.6Å×108.6Å×108.6Å) of diamond cubic structure of Si, then carbon atoms were placed randomly at 5% intervals from 0-50 percent C. Results show improved mechanical properties when increasing percent C until peaking at 25%, before decreasing. This is caused by the shortest bond length at 25 percent C from the increase of Si=C using the Radial Distribution Function analysis. Increasing the strain rate generally improves the mechanical properties of the material. The deformation mechanism shows that increasing (decreasing) strain rate generally results in multiple (lesser) failure points with a ductile (brittle) fracture mode.","PeriodicalId":505044,"journal":{"name":"Japanese Journal of Applied Physics","volume":"45 3","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-07-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141806927","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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