Pub Date : 2024-09-18DOI: 10.35848/1347-4065/ad7554
Xuefeng Xiao, Yan Huang, Yan Zhang, Jiashun Si, Shuaijie Liang, Qingyan Xu, Huan Zhang, Lingling Ma, Cui Yang, Xuefeng Zhang, Jiayue Xu, Tian Tian and Hui Shen
This paper is based on the first principles of density functional theory and uses the virtual crystal approximation method to calculate and analyze the optical properties of differently proportioned Eu3+-doped Bismuth silicate (Bi4Si3O12, or BSO). The results show that minor Eu3+ doping (1/12–1/3) improves the polarization ability of BSO and reduces energy loss. Additionally, doping an appropriate amount of Eu3+ (1/12–1/3) can improve light absorption and transmission of BSO to some extent. That is to say, Eu3+ doping improves the response of BSO to infrared light, and the absorption capacity in the ultraviolet and visible light regions is also enhanced. The theoretical research in this paper elucidates the changes in the optical properties of BSO after doping with Eu3+, providing a theoretical basis for expanding its application as a scintillation crystal in high-energy physics experiments, nuclear medicine, and other fields.
{"title":"Research on optical properties of Eu3+ doped bismuth silicate crystals based on first principles","authors":"Xuefeng Xiao, Yan Huang, Yan Zhang, Jiashun Si, Shuaijie Liang, Qingyan Xu, Huan Zhang, Lingling Ma, Cui Yang, Xuefeng Zhang, Jiayue Xu, Tian Tian and Hui Shen","doi":"10.35848/1347-4065/ad7554","DOIUrl":"https://doi.org/10.35848/1347-4065/ad7554","url":null,"abstract":"This paper is based on the first principles of density functional theory and uses the virtual crystal approximation method to calculate and analyze the optical properties of differently proportioned Eu3+-doped Bismuth silicate (Bi4Si3O12, or BSO). The results show that minor Eu3+ doping (1/12–1/3) improves the polarization ability of BSO and reduces energy loss. Additionally, doping an appropriate amount of Eu3+ (1/12–1/3) can improve light absorption and transmission of BSO to some extent. That is to say, Eu3+ doping improves the response of BSO to infrared light, and the absorption capacity in the ultraviolet and visible light regions is also enhanced. The theoretical research in this paper elucidates the changes in the optical properties of BSO after doping with Eu3+, providing a theoretical basis for expanding its application as a scintillation crystal in high-energy physics experiments, nuclear medicine, and other fields.","PeriodicalId":14741,"journal":{"name":"Japanese Journal of Applied Physics","volume":"36 1","pages":""},"PeriodicalIF":1.5,"publicationDate":"2024-09-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142247979","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 : 2024-09-18DOI: 10.35848/1347-4065/ad6e96
Kohei Maruyama, Yoshihiro Kawakami and Fumio Narita
In this study, we employed corona poling to improve the piezoelectric properties of as-deposited BaTiO3 films and conducted a vibration energy harvesting test. Dielectric measurements indicated that the dielectric constant of the as-deposited film increased with temperature, and the frequency dependence of the dielectric constant was minimal at room temperature. Applying an electric field of 1500 kV cm−1 resulted in a recoverable energy density of 7.1 J cm−3 and an energy storage efficiency of 54%. The corona polarization treatment could align dipoles under high electric fields and prevent dielectric breakdown owing to local defects created by the aerosol deposition (AD) process. The vibration test yielded a harvested energy of 172 nJ and an output voltage of 2.67 V, which is suitable for force sensor applications. Polarization via corona discharge is also feasible without an electrode. Integrating AD with corona poling may benefit new capacitors, sensors, and energy harvesting technologies.
{"title":"Thick piezoelectric films by aerosol deposition at room temperature: corona poling and force sensing","authors":"Kohei Maruyama, Yoshihiro Kawakami and Fumio Narita","doi":"10.35848/1347-4065/ad6e96","DOIUrl":"https://doi.org/10.35848/1347-4065/ad6e96","url":null,"abstract":"In this study, we employed corona poling to improve the piezoelectric properties of as-deposited BaTiO3 films and conducted a vibration energy harvesting test. Dielectric measurements indicated that the dielectric constant of the as-deposited film increased with temperature, and the frequency dependence of the dielectric constant was minimal at room temperature. Applying an electric field of 1500 kV cm−1 resulted in a recoverable energy density of 7.1 J cm−3 and an energy storage efficiency of 54%. The corona polarization treatment could align dipoles under high electric fields and prevent dielectric breakdown owing to local defects created by the aerosol deposition (AD) process. The vibration test yielded a harvested energy of 172 nJ and an output voltage of 2.67 V, which is suitable for force sensor applications. Polarization via corona discharge is also feasible without an electrode. Integrating AD with corona poling may benefit new capacitors, sensors, and energy harvesting technologies.","PeriodicalId":14741,"journal":{"name":"Japanese Journal of Applied Physics","volume":"10 1","pages":""},"PeriodicalIF":1.5,"publicationDate":"2024-09-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142247977","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 : 2024-09-18DOI: 10.35848/1347-4065/ad6e92
Yugo Nakahama and Kazunori Takahashi
Argon gas is injected from a back plate having either a radial center hole or shower-patterned eight holes into a 13.3-cm-diameter and 25-cm-long radio frequency (rf) plasma source attached to a 43.7-cm-diameter and 65cm-long diffusion chamber under an expanding magnetic field, which resembles the magnetic nozzle rf plasma thruster. The source has a double-turn loop antenna powered by a 13.56 MHz rf generator at a maximum power level of ~2.8 kW in low-pressure argon, providing a plasma density of about 1018 m−3 in the source. A high plasma density and a slightly low electron temperature are obtained for the shower-pattered case in both the source tube and the diffusion chamber, compared with the center hole case, suggesting that the neutral density profile significantly affects the plasma density profile. This result will provide an improvement in the thruster performance by the gas injection pattern.
{"title":"Effect of gas injection pattern on magnetically expanding rf plasma source","authors":"Yugo Nakahama and Kazunori Takahashi","doi":"10.35848/1347-4065/ad6e92","DOIUrl":"https://doi.org/10.35848/1347-4065/ad6e92","url":null,"abstract":"Argon gas is injected from a back plate having either a radial center hole or shower-patterned eight holes into a 13.3-cm-diameter and 25-cm-long radio frequency (rf) plasma source attached to a 43.7-cm-diameter and 65cm-long diffusion chamber under an expanding magnetic field, which resembles the magnetic nozzle rf plasma thruster. The source has a double-turn loop antenna powered by a 13.56 MHz rf generator at a maximum power level of ~2.8 kW in low-pressure argon, providing a plasma density of about 1018 m−3 in the source. A high plasma density and a slightly low electron temperature are obtained for the shower-pattered case in both the source tube and the diffusion chamber, compared with the center hole case, suggesting that the neutral density profile significantly affects the plasma density profile. This result will provide an improvement in the thruster performance by the gas injection pattern.","PeriodicalId":14741,"journal":{"name":"Japanese Journal of Applied Physics","volume":"33 1","pages":""},"PeriodicalIF":1.5,"publicationDate":"2024-09-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142268305","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}
For the 3D NAND memory hole with a high aspect ratio above 100, the etching process with hydrogen-fluoride (HF) contained plasmas has been proposed. We have developed a simulation model for gas-phase reactions that reproduces the HF plasma in experiments. The HF plasma was generated using a power supply of 100 MHz frequency, and electron and F densities were measured. The simulation model was constructed on the basis of the collision cross sections and reaction constants reported in the previous papers, and the F density in the simulation was calibrated by comparing it with that in the experiments. As a result of the plasma simulation, the densities of F and the electrons were determined to be 7.52 × 1016 m–3 and 8.50 × 1016 m–3, respectively. Taking into consideration the errors in the experiment, we considered that the simulation model is able to reproduce the experimental HF plasma well.
对于高宽比超过 100 的三维 NAND 存储孔，有人提出了使用含氟化氢（HF）等离子体的蚀刻工艺。我们开发了一个气相反应仿真模型，可以再现实验中的高频等离子体。我们使用频率为 100 MHz 的电源生成高频等离子体，并测量了电子密度和 F 密度。模拟模型是根据以前论文中报告的碰撞截面和反应常数建立的，模拟中的 F 密度是通过与实验中的 F 密度进行比较而校准的。通过等离子体模拟，确定 F 密度和电子密度分别为 7.52 × 1016 m-3 和 8.50 × 1016 m-3。考虑到实验中的误差，我们认为模拟模型能够很好地再现实验中的高频等离子体。
{"title":"Plasma simulation of HF plasma generated in dual-frequency chamber for high aspect ratio dielectric etching","authors":"Shigeyuki Takagi, Shih-Nan Hsiao, Chih-Yu Ma, Makoto Sekine and Fumihiko Matsunaga","doi":"10.35848/1347-4065/ad6e91","DOIUrl":"https://doi.org/10.35848/1347-4065/ad6e91","url":null,"abstract":"For the 3D NAND memory hole with a high aspect ratio above 100, the etching process with hydrogen-fluoride (HF) contained plasmas has been proposed. We have developed a simulation model for gas-phase reactions that reproduces the HF plasma in experiments. The HF plasma was generated using a power supply of 100 MHz frequency, and electron and F densities were measured. The simulation model was constructed on the basis of the collision cross sections and reaction constants reported in the previous papers, and the F density in the simulation was calibrated by comparing it with that in the experiments. As a result of the plasma simulation, the densities of F and the electrons were determined to be 7.52 × 1016 m–3 and 8.50 × 1016 m–3, respectively. Taking into consideration the errors in the experiment, we considered that the simulation model is able to reproduce the experimental HF plasma well.","PeriodicalId":14741,"journal":{"name":"Japanese Journal of Applied Physics","volume":"20 1","pages":""},"PeriodicalIF":1.5,"publicationDate":"2024-09-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142268306","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 : 2024-09-17DOI: 10.35848/1347-4065/ad750d
Yining Jiao, Masanobu Takahashi, Taketomo Sato and Masamichi Akazawa
In this paper, we report the effects of 800 °C SiO2 cap annealing on the Al2O3/p-type GaN (p-GaN):Mg and SiO2/p-GaN:Mg interfaces formed at relatively low temperatures, as determined by X-ray photoelectron spectroscopy (XPS) and sub-bandgap-light-assisted capacitance–voltage (C–V) measurement. For the sample with capless annealing at 800 °C and subsequent HF treatment before the Al2O3/p-GaN interface formation by atomic layer deposition at 300 °C, its C–V characteristics indicated the existence of high-density midgap states. By SiO2 cap annealing and subsequent HF treatment to remove the cap layer, we found that the Al2O3/p-GaN interface showed a reduction in midgap state density. The same effect was confirmed at the SiO2/p-GaN interface. Taking this finding and XPS results together, we consider the possibility that SiO2 cap annealing at 800 °C and the subsequent HF treatment prior to the formation of the Al2O3/p-GaN and SiO2/p-GaN interfaces led to the reduction of interface disorder.
{"title":"Effects of SiO2 cap annealing on MOS interfaces formed on Mg-doped p-type GaN surface","authors":"Yining Jiao, Masanobu Takahashi, Taketomo Sato and Masamichi Akazawa","doi":"10.35848/1347-4065/ad750d","DOIUrl":"https://doi.org/10.35848/1347-4065/ad750d","url":null,"abstract":"In this paper, we report the effects of 800 °C SiO2 cap annealing on the Al2O3/p-type GaN (p-GaN):Mg and SiO2/p-GaN:Mg interfaces formed at relatively low temperatures, as determined by X-ray photoelectron spectroscopy (XPS) and sub-bandgap-light-assisted capacitance–voltage (C–V) measurement. For the sample with capless annealing at 800 °C and subsequent HF treatment before the Al2O3/p-GaN interface formation by atomic layer deposition at 300 °C, its C–V characteristics indicated the existence of high-density midgap states. By SiO2 cap annealing and subsequent HF treatment to remove the cap layer, we found that the Al2O3/p-GaN interface showed a reduction in midgap state density. The same effect was confirmed at the SiO2/p-GaN interface. Taking this finding and XPS results together, we consider the possibility that SiO2 cap annealing at 800 °C and the subsequent HF treatment prior to the formation of the Al2O3/p-GaN and SiO2/p-GaN interfaces led to the reduction of interface disorder.","PeriodicalId":14741,"journal":{"name":"Japanese Journal of Applied Physics","volume":"13 1","pages":""},"PeriodicalIF":1.5,"publicationDate":"2024-09-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142247982","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 : 2024-09-17DOI: 10.35848/1347-4065/ad759a
S. Kodate, Q. Shi and S. Kajita
Pulsed laser deposition (PLD) under gas atmospheres has been used to fabricate thin films for various applications. In this study, PLD was performed under various gas atmospheres (helium, oxygen, and argon) using tungsten (W) to investigate the morphology of thin films. Various types of structures were formed, including uniform, nanoparticles, and columnar structures. In particular, the substrate fabricated at an argon pressure of 100 Pa had a high porosity and a low light reflectance in the 200–1400 nm wavelength range. In addition, it was shown that the growth of the thin film thickness was non-linear with respect to time, and the formation of a fuzz-like structure may be influenced by particle diffusion in the gas phase and on the substrate.
气体环境下的脉冲激光沉积（PLD）已被用于制造各种用途的薄膜。本研究使用钨（W）在各种气体环境（氦气、氧气和氩气）下进行了脉冲激光沉积，以研究薄膜的形态。形成了各种类型的结构，包括均匀结构、纳米颗粒结构和柱状结构。特别是在氩气压力为 100 Pa 时制造的基底具有高孔隙率和 200-1400 nm 波长范围内的低光反射率。此外，研究还表明，薄膜厚度的增长与时间呈非线性关系，绒毛状结构的形成可能受到气相中和基底上颗粒扩散的影响。
{"title":"Formation conditions of the tungsten porous thin film with pulsed laser deposition under various gas atmosphere","authors":"S. Kodate, Q. Shi and S. Kajita","doi":"10.35848/1347-4065/ad759a","DOIUrl":"https://doi.org/10.35848/1347-4065/ad759a","url":null,"abstract":"Pulsed laser deposition (PLD) under gas atmospheres has been used to fabricate thin films for various applications. In this study, PLD was performed under various gas atmospheres (helium, oxygen, and argon) using tungsten (W) to investigate the morphology of thin films. Various types of structures were formed, including uniform, nanoparticles, and columnar structures. In particular, the substrate fabricated at an argon pressure of 100 Pa had a high porosity and a low light reflectance in the 200–1400 nm wavelength range. In addition, it was shown that the growth of the thin film thickness was non-linear with respect to time, and the formation of a fuzz-like structure may be influenced by particle diffusion in the gas phase and on the substrate.","PeriodicalId":14741,"journal":{"name":"Japanese Journal of Applied Physics","volume":"190 1","pages":""},"PeriodicalIF":1.5,"publicationDate":"2024-09-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142247980","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 : 2024-09-17DOI: 10.35848/1347-4065/ad7553
Hideyuki Sugioka, Daisuke Sumida and Kazuma Matsuo
Powerful micropumps and water treatment are essential for biomedical applications using microfluidic circuits. Therefore, we propose a rotary pump using underwater electrical discharge for biomedical applications and elucidate its design concept. Specifically, we demonstrate that by applying high-voltage pulses repeatedly, the rotary device having an asymmetrical antenna structure can rotate with the maximum angular velocity of ∼25 rad s−1, and can produce a net flow with an average velocity of ∼3.2 mm s−1 along with an instantaneous maximum flow of ∼9 mm s−1. In addition, we explain our experimental results fairly well by proposing a simple model that considers the effects of asymmetricity and electric field strength with a steric effect. Our findings should contribute to the microfluidics for biomedical applications.
使用微流控电路的生物医学应用离不开功能强大的微泵和水处理。因此，我们提出了一种用于生物医学应用的水下放电旋转泵，并阐明了其设计理念。具体而言，我们证明了通过反复施加高压脉冲，具有非对称天线结构的旋转装置可以以 25 rad s-1 的最大角速度旋转，并能产生平均速度为 3.2 mm s-1 的净流量和 9 mm s-1 的瞬时最大流量。此外，我们还提出了一个简单的模型，考虑了不对称和电场强度以及立体效应的影响，从而很好地解释了我们的实验结果。我们的研究结果将有助于微流控技术在生物医学领域的应用。
{"title":"Rotary pump using underwater electrical discharge","authors":"Hideyuki Sugioka, Daisuke Sumida and Kazuma Matsuo","doi":"10.35848/1347-4065/ad7553","DOIUrl":"https://doi.org/10.35848/1347-4065/ad7553","url":null,"abstract":"Powerful micropumps and water treatment are essential for biomedical applications using microfluidic circuits. Therefore, we propose a rotary pump using underwater electrical discharge for biomedical applications and elucidate its design concept. Specifically, we demonstrate that by applying high-voltage pulses repeatedly, the rotary device having an asymmetrical antenna structure can rotate with the maximum angular velocity of ∼25 rad s−1, and can produce a net flow with an average velocity of ∼3.2 mm s−1 along with an instantaneous maximum flow of ∼9 mm s−1. In addition, we explain our experimental results fairly well by proposing a simple model that considers the effects of asymmetricity and electric field strength with a steric effect. Our findings should contribute to the microfluidics for biomedical applications.","PeriodicalId":14741,"journal":{"name":"Japanese Journal of Applied Physics","volume":"17 1","pages":""},"PeriodicalIF":1.5,"publicationDate":"2024-09-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142247978","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 : 2024-09-17DOI: 10.35848/1347-4065/ad750c
Akihisa Ogino, Yuto Kato and Ryotaro Kito
MoS2 synthesis methods with fewer grain boundaries are expected for device applications. To control the nucleation density and to increase the domain size of MoS2 on a Si substrate, MoS2 was synthesized on a fluorine-terminated Si substrate prepared by SF6 mixed gas plasma. The average domain size of monolayer MoS2 synthesized on a fluorine-terminated Si substrate was several times larger than that on a pristine Si substrate, and grain boundaries were reduced. The MoS2 synthesized on the fluorine-terminated substrate was found to have improved crystallinity based on the results of Raman and photoluminescence spectroscopy. XPS analysis showed that no residual fluoride was observed on the substrate surface after CVD, suggesting that fluorine atoms were volatilized together with Mo by chemical reaction during CVD. Fluorine-terminated surfaces prepared by SF6 mixed gas plasma contribute to increasing the domain size of MoS2, and it can be applied for selective growth in the subsequent CVD synthesis of MoS2.
{"title":"MoS2 synthesis on fluorine-terminated Si substrates prepared by SF6 mixed gas plasma","authors":"Akihisa Ogino, Yuto Kato and Ryotaro Kito","doi":"10.35848/1347-4065/ad750c","DOIUrl":"https://doi.org/10.35848/1347-4065/ad750c","url":null,"abstract":"MoS2 synthesis methods with fewer grain boundaries are expected for device applications. To control the nucleation density and to increase the domain size of MoS2 on a Si substrate, MoS2 was synthesized on a fluorine-terminated Si substrate prepared by SF6 mixed gas plasma. The average domain size of monolayer MoS2 synthesized on a fluorine-terminated Si substrate was several times larger than that on a pristine Si substrate, and grain boundaries were reduced. The MoS2 synthesized on the fluorine-terminated substrate was found to have improved crystallinity based on the results of Raman and photoluminescence spectroscopy. XPS analysis showed that no residual fluoride was observed on the substrate surface after CVD, suggesting that fluorine atoms were volatilized together with Mo by chemical reaction during CVD. Fluorine-terminated surfaces prepared by SF6 mixed gas plasma contribute to increasing the domain size of MoS2, and it can be applied for selective growth in the subsequent CVD synthesis of MoS2.","PeriodicalId":14741,"journal":{"name":"Japanese Journal of Applied Physics","volume":"14 1","pages":""},"PeriodicalIF":1.5,"publicationDate":"2024-09-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142247981","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 : 2024-09-16DOI: 10.35848/1347-4065/ad6e8f
Aina Hiyama Zazuli, Taketo Kowaki, Minagi Miyamoto, Koki Hanasaku, Daisuke Inahara, Kai Fujii, Taisei Kimoto, Ryosuke Ninoki, Satoshi Kurai, Narihito Okada and Yoichi Yamada
In this study, we attempted to fabricate N-polar GaN/AlGaN/AlN heterostructure FET by changing the thickness of the AlN layer. An Al-polar tiny-pit AlN layer and a polarity inversion method were used to grow N-polar AlN on vicinal sapphire via the metal-organic vapor phase epitaxy. The samples with an AlN thickness of up to 3.4 μm exhibited a crack-free surface. Additionally, the twist component of the crystal quality improved with an increasing AlN thickness. Consequently, the mobility, sheet conductivity, and surface flatness improved. The FET fabricated from the sample with a thicker AlN layer achieved a higher drain current of 279 mA mm−1 at a gate bias of VG = 3 V.
在这项研究中，我们尝试通过改变氮化镓层的厚度来制造 N 极 GaN/AlGaN/AlN 异质结构场效应晶体管。通过金属有机气相外延技术，我们在沧桑蓝宝石上使用了铝极性微坑 AlN 层和极性反转方法来生长 N 极性 AlN。AlN 厚度达 3.4 μm 的样品表面无裂纹。此外，随着 AlN 厚度的增加，晶体质量的扭曲成分也有所改善。因此，迁移率、薄片电导率和表面平整度也得到了改善。在栅极偏压为 VG = 3 V 时，用更厚 AlN 层的样品制造的 FET 的漏极电流高达 279 mA mm-1。
{"title":"Impact of thick N-polar AlN growth on crystalline quality and electrical properties of N-polar GaN/AlGaN/AlN FET","authors":"Aina Hiyama Zazuli, Taketo Kowaki, Minagi Miyamoto, Koki Hanasaku, Daisuke Inahara, Kai Fujii, Taisei Kimoto, Ryosuke Ninoki, Satoshi Kurai, Narihito Okada and Yoichi Yamada","doi":"10.35848/1347-4065/ad6e8f","DOIUrl":"https://doi.org/10.35848/1347-4065/ad6e8f","url":null,"abstract":"In this study, we attempted to fabricate N-polar GaN/AlGaN/AlN heterostructure FET by changing the thickness of the AlN layer. An Al-polar tiny-pit AlN layer and a polarity inversion method were used to grow N-polar AlN on vicinal sapphire via the metal-organic vapor phase epitaxy. The samples with an AlN thickness of up to 3.4 μm exhibited a crack-free surface. Additionally, the twist component of the crystal quality improved with an increasing AlN thickness. Consequently, the mobility, sheet conductivity, and surface flatness improved. The FET fabricated from the sample with a thicker AlN layer achieved a higher drain current of 279 mA mm−1 at a gate bias of VG = 3 V.","PeriodicalId":14741,"journal":{"name":"Japanese Journal of Applied Physics","volume":"3 1","pages":""},"PeriodicalIF":1.5,"publicationDate":"2024-09-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142247983","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 : 2024-09-16DOI: 10.35848/1347-4065/ad6e94
Chenxu Wang, Hideki Kawaguchi, Hiroaki Nakamura and Shin Kubo
It is pointed out that the millimeter-wave vortex may contribute to an efficient method of plasma heating since it was found that the millimeter-wave vortex can propagate in magnetized plasma even in which the normal plane wave is in cut-off condition. Then, it was assumed that the vortex field was the Laguerre–Gaussian (L–G) mode which is a free-space solution, but the generation and stable propagation of the L–G mode vortex are not easy in the millimeter frequency range. On the other hand, it is known that the millimeter-wave hybrid mode of the cylindrical corrugated waveguide also has vortex properties. In this paper, we investigate the propagation characteristics of a millimeter-wave vortex of a hybrid mode of a cylindrical corrugated waveguide in the magnetized plasma by using three-dimensional numerical simulations with the finite-difference time-domain (FDTD) method. It is found that the millimeter-wave vortex of hybrid mode also can propagate in the magnetized plasma even in a condition in which the normal plane wave is in cut-off condition, and the propagation power in the plasma is highly dependent on the topological charge l.
研究指出，毫米波漩涡可能有助于一种有效的等离子体加热方法，因为研究发现，即使正常平面波处于截止状态，毫米波漩涡也能在磁化等离子体中传播。然后，假设涡旋场是拉盖尔-高斯（L-G）模式，这是一种自由空间解，但在毫米波频率范围内，L-G 模式涡旋的产生和稳定传播并不容易。另一方面，已知圆柱波纹波导的毫米波混合模式也具有漩涡特性。本文采用有限差分时域（FDTD）方法进行三维数值模拟，研究了磁化等离子体中圆柱波纹波导混合模式毫米波涡旋的传播特性。研究发现，即使在法向平面波处于截止状态的条件下，混合模式的毫米波涡旋也能在磁化等离子体中传播，而且等离子体中的传播功率与拓扑电荷 l 高度相关。
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