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}
Pub Date : 2024-08-20DOI: 10.35848/1347-4065/ad68e0
Yuki Matsunaga, Haruki Uchiyama, Haruka Omachi, Jun Hirotani
Chemical doping of carbon nanotubes (CNTs) by adsorption with high-temperature-tolerant molecules is required for the fabrication of various types of electronic devices for their performance maintenance under harsh thermal conditions during the fabrication and operation processes. Here, we demonstrate the fabrication of CNT thin film pn junction diodes using a combination of 1,4,5,8,9,11-hexaazatriphenylenehexacarbonitrile as a p-dopant and a complex salt of potassium hydroxide and benzo-18-crown-6 ether as an n-dopant. The fabricated devices demonstrated a reasonably stable rectifying behavior, even after heating to 200 °C for 300 min.
通过吸附耐高温分子对碳纳米管（CNTs）进行化学掺杂是制造各类电子器件所必需的，以便在制造和运行过程中的苛刻热条件下保持其性能。在此，我们展示了以 1,4,5,8,9,11-六氮杂三苯六腈作为 p 掺杂剂，以氢氧化钾和苯并-18-冠醚的复盐作为 n 掺杂剂，制备 CNT 薄膜 pn 结二极管的过程。即使在加热到 200 °C 300 分钟后，所制造的器件仍能表现出相当稳定的整流特性。
{"title":"Carbon nanotube thin film pn junction diode with high-temperature tolerance using chemical dopants","authors":"Yuki Matsunaga, Haruki Uchiyama, Haruka Omachi, Jun Hirotani","doi":"10.35848/1347-4065/ad68e0","DOIUrl":"https://doi.org/10.35848/1347-4065/ad68e0","url":null,"abstract":"Chemical doping of carbon nanotubes (CNTs) by adsorption with high-temperature-tolerant molecules is required for the fabrication of various types of electronic devices for their performance maintenance under harsh thermal conditions during the fabrication and operation processes. Here, we demonstrate the fabrication of CNT thin film pn junction diodes using a combination of 1,4,5,8,9,11-hexaazatriphenylenehexacarbonitrile as a p-dopant and a complex salt of potassium hydroxide and benzo-18-crown-6 ether as an n-dopant. The fabricated devices demonstrated a reasonably stable rectifying behavior, even after heating to 200 °C for 300 min.","PeriodicalId":14741,"journal":{"name":"Japanese Journal of Applied Physics","volume":"39 1","pages":""},"PeriodicalIF":1.5,"publicationDate":"2024-08-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142218131","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 study, we developed C60 reactive diamond composite particles for the chemical mechanical polishing (CMP) of diamond substrates by applying the high hardness and high reactivity of the C60 molecule. When diamond substrates were polished using these C60 diamond composite particles, the polished surface was found to be superior to that of diamond particles. In addition, when the composite particles were irradiated with ultraviolet light to produce polishing fine particles, the polishing rate was improved by about 30%. These results indicate that the composite nanoparticles that reacted with C60 have the potential to remove even the hardest of diamond substrates.
{"title":"Study on carbon allotrope abrasive particles based on C60 molecule for diamond chemical mechanical polishing","authors":"Junpei Takeiri, Keisuke Suzuki, Hiroaki Iura, Taisuke Hantani, Masaki Morii, Hideaki Nisizawa","doi":"10.35848/1347-4065/ad59e9","DOIUrl":"https://doi.org/10.35848/1347-4065/ad59e9","url":null,"abstract":"In this study, we developed C<sub>60</sub> reactive diamond composite particles for the chemical mechanical polishing (CMP) of diamond substrates by applying the high hardness and high reactivity of the C<sub>60</sub> molecule. When diamond substrates were polished using these C<sub>60</sub> diamond composite particles, the polished surface was found to be superior to that of diamond particles. In addition, when the composite particles were irradiated with ultraviolet light to produce polishing fine particles, the polishing rate was improved by about 30%. These results indicate that the composite nanoparticles that reacted with C<sub>60</sub> have the potential to remove even the hardest of diamond substrates.","PeriodicalId":14741,"journal":{"name":"Japanese Journal of Applied Physics","volume":"82 1","pages":""},"PeriodicalIF":1.5,"publicationDate":"2024-08-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142218132","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 : 2024-08-05DOI: 10.35848/1347-4065/ad5921
Most Tauhida Tabassum, Yusuke Nakagawa and Fumiyoshi Tochikubo
The decomposition of Cu-Ethylenediaminetetraacetic Acid (Cu-EDTA) using a pulsed streamer discharge in contact with liquid is reported under various experimental conditions, and the efficacy of OH radicals is investigated. The change in Cu-EDTA concentration was characterized using high-performance liquid chromatography. H2O2, NO2−, NO3−, and O3 were detected using water inspection test kits and an UV-visual spectrophotometer. The OH yield was estimated using a colorimetric method with disodium terephthalate. The results revealed that approximately 70% of the Cu-EDTA decomposed with an energy efficiency of 15 mmol kWh−1 in the Ar discharge, whereas the decomposition rate and energy efficiency in the air discharge were 80% and 16 mmol kWh−1, respectively, within 60 min of treatment. The decomposition in Ar was primarily driven by the OH generated during discharge, whereas a combined effect of O3 and OH was observed during air discharge. The discharge-generated OH was the dominant species in Cu-EDTA decomposition in this study.
{"title":"Investigation of the decomposition performances of Cu-EDTA using pulsed streamer discharge","authors":"Most Tauhida Tabassum, Yusuke Nakagawa and Fumiyoshi Tochikubo","doi":"10.35848/1347-4065/ad5921","DOIUrl":"https://doi.org/10.35848/1347-4065/ad5921","url":null,"abstract":"The decomposition of Cu-Ethylenediaminetetraacetic Acid (Cu-EDTA) using a pulsed streamer discharge in contact with liquid is reported under various experimental conditions, and the efficacy of OH radicals is investigated. The change in Cu-EDTA concentration was characterized using high-performance liquid chromatography. H2O2, NO2−, NO3−, and O3 were detected using water inspection test kits and an UV-visual spectrophotometer. The OH yield was estimated using a colorimetric method with disodium terephthalate. The results revealed that approximately 70% of the Cu-EDTA decomposed with an energy efficiency of 15 mmol kWh−1 in the Ar discharge, whereas the decomposition rate and energy efficiency in the air discharge were 80% and 16 mmol kWh−1, respectively, within 60 min of treatment. The decomposition in Ar was primarily driven by the OH generated during discharge, whereas a combined effect of O3 and OH was observed during air discharge. The discharge-generated OH was the dominant species in Cu-EDTA decomposition in this study.","PeriodicalId":14741,"journal":{"name":"Japanese Journal of Applied Physics","volume":"21 1","pages":""},"PeriodicalIF":1.5,"publicationDate":"2024-08-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141939419","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}
Acoustic metasurfaces have shown great promise for applications in many acoustic wave modulation fields, while the use of intelligent optimization algorithms has facilitated the design of acoustic metasurfaces. In this paper, we utilize the stop band properties of phononic crystals to design a metasurface that can achieve both transmission focusing and reflection focusing, as well as a metasurface that utilizes acoustic focusing to filter the incident acoustic wave. In order to achieve the best effect, this paper uses the taboo genetic algorithm to optimize the arrangement order of the structural units controlling different focuses in the acoustic metasurface, and the optimization achieves a good focusing effect, which expands the design of acoustic metasurfaces as well as the application scenarios of acoustic focusing.
{"title":"A study of acoustic focusing based on the taboo genetic algorithm","authors":"Shulei Gong, Jinyu Zhao, Mengchun Yang, Zihao Liu, Yuan Liu, Yongchang Li","doi":"10.35848/1347-4065/ad5b9f","DOIUrl":"https://doi.org/10.35848/1347-4065/ad5b9f","url":null,"abstract":"Acoustic metasurfaces have shown great promise for applications in many acoustic wave modulation fields, while the use of intelligent optimization algorithms has facilitated the design of acoustic metasurfaces. In this paper, we utilize the stop band properties of phononic crystals to design a metasurface that can achieve both transmission focusing and reflection focusing, as well as a metasurface that utilizes acoustic focusing to filter the incident acoustic wave. In order to achieve the best effect, this paper uses the taboo genetic algorithm to optimize the arrangement order of the structural units controlling different focuses in the acoustic metasurface, and the optimization achieves a good focusing effect, which expands the design of acoustic metasurfaces as well as the application scenarios of acoustic focusing.","PeriodicalId":14741,"journal":{"name":"Japanese Journal of Applied Physics","volume":"1 1","pages":""},"PeriodicalIF":1.5,"publicationDate":"2024-07-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141870959","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 : 2024-07-24DOI: 10.35848/1347-4065/ad5b32
Meita Asami, Kentaroh Watanabe, Yoshiaki Nakano and Masakazu Sugiyama
The escalating demand for improved energy conversion efficiency in vehicular applications of solar cells underscores the need for innovative solutions. This study focuses on enhancing the current density of GaAs middle cells within conventional Ge-based triple-junction solar cells to realize unprecedented levels of energy conversion efficiency. We introduced a novel superlattice configuration termed a compressively strained superlattice (CSSL) and demonstrated its integration into a p-i-n junction GaAs solar cell, achieving a current density increase of 1.03 mA cm−2 over conventional GaAs solar cells. Prior investigations have explored a strain-balanced superlattice (SBSL) to enhance GaAs middle cell current density. However, our findings establish the superiority of the CSSL over the SBSL in terms of current density improvement, with the CSSL featuring 1.59 times more quantum wells per unit length than the SBSL. This increase in quantum well quantity significantly enhances light absorption efficiency and consequently, the current density.
{"title":"Boosting quantum-structured solar cell light absorption through compressively strained superlattices","authors":"Meita Asami, Kentaroh Watanabe, Yoshiaki Nakano and Masakazu Sugiyama","doi":"10.35848/1347-4065/ad5b32","DOIUrl":"https://doi.org/10.35848/1347-4065/ad5b32","url":null,"abstract":"The escalating demand for improved energy conversion efficiency in vehicular applications of solar cells underscores the need for innovative solutions. This study focuses on enhancing the current density of GaAs middle cells within conventional Ge-based triple-junction solar cells to realize unprecedented levels of energy conversion efficiency. We introduced a novel superlattice configuration termed a compressively strained superlattice (CSSL) and demonstrated its integration into a p-i-n junction GaAs solar cell, achieving a current density increase of 1.03 mA cm−2 over conventional GaAs solar cells. Prior investigations have explored a strain-balanced superlattice (SBSL) to enhance GaAs middle cell current density. However, our findings establish the superiority of the CSSL over the SBSL in terms of current density improvement, with the CSSL featuring 1.59 times more quantum wells per unit length than the SBSL. This increase in quantum well quantity significantly enhances light absorption efficiency and consequently, the current density.","PeriodicalId":14741,"journal":{"name":"Japanese Journal of Applied Physics","volume":"19 1","pages":""},"PeriodicalIF":1.5,"publicationDate":"2024-07-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141773482","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 : 2024-07-22DOI: 10.35848/1347-4065/ad5cb2
Hironori Okumura and Joel B. Varley
We reported the growth of (AlGa)2O3 layers on (10 ) α-Al2O3 substrates using cold-wall metalorganic chemical vapor deposition, and the electrical characterization of Si-doped (AlGa)2O3 layers. In the Ga2O3 growth, the α phase was dominant at low growth temperature, achieving the growth rate of 2.4 μm h−1 at 650 °C. Sheet resistance and electrical conductivity of the Ga2O3 layers with a Si concentration of 3 × 1020 cm−3 were 1 × 104 Ω/square and 8.3 S cm−1, respectively, at the measurement temperature of 500 °C. The Al composition in the (AlGa)2O3 layers was controlled from 0% to 74%. In our initial attempts, we obtained electrically conductive α-(AlGa)2O3 layers by Si doping (2 × 10−9 S cm−1 in the sample with an Al composition of 56%). Hybrid functional calculations suggest the conductivities are limited by compensation of Si through cation vacancy complexes, and not by the significant amounts of co-incorporated C and N that are predicted to be electrically passivated by hydrogen.
{"title":"MOCVD growth of Si-doped α-(AlGa)2O3 on m-plane α-Al2O3 substrates","authors":"Hironori Okumura and Joel B. Varley","doi":"10.35848/1347-4065/ad5cb2","DOIUrl":"https://doi.org/10.35848/1347-4065/ad5cb2","url":null,"abstract":"We reported the growth of (AlGa)2O3 layers on (10 ) α-Al2O3 substrates using cold-wall metalorganic chemical vapor deposition, and the electrical characterization of Si-doped (AlGa)2O3 layers. In the Ga2O3 growth, the α phase was dominant at low growth temperature, achieving the growth rate of 2.4 μm h−1 at 650 °C. Sheet resistance and electrical conductivity of the Ga2O3 layers with a Si concentration of 3 × 1020 cm−3 were 1 × 104 Ω/square and 8.3 S cm−1, respectively, at the measurement temperature of 500 °C. The Al composition in the (AlGa)2O3 layers was controlled from 0% to 74%. In our initial attempts, we obtained electrically conductive α-(AlGa)2O3 layers by Si doping (2 × 10−9 S cm−1 in the sample with an Al composition of 56%). Hybrid functional calculations suggest the conductivities are limited by compensation of Si through cation vacancy complexes, and not by the significant amounts of co-incorporated C and N that are predicted to be electrically passivated by hydrogen.","PeriodicalId":14741,"journal":{"name":"Japanese Journal of Applied Physics","volume":"43 1","pages":""},"PeriodicalIF":1.5,"publicationDate":"2024-07-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141773485","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 : 2024-07-22DOI: 10.35848/1347-4065/ad5afe
Shin Kajita, Quan Shi, Kiho Tabata, Tatsuya Kuwabara, Hirohiko Tanaka and Noriyasu Ohno
The effects of helium plasma irradiation, which has been widely studied on metals, on germanium have been experimentally investigated. The irradiation temperature ranges from 430 to 720 K, and the incident ion energy ranges from 30 to 100 eV. From the scanning electron microscope (SEM) observation, it was found that various morphological changes including pits, nanocones, nanopillars, and roughened surfaces occur. The spatial scale of the morphological change was analyzed by applying fast Fourier transform to SEM micrographs. Thermal desorption spectroscopy analysis suggests that He atoms implanted on Ge play major roles in forming roughened surfaces at a surface temperature higher than 500 K.
实验研究了氦等离子体辐照对锗的影响，氦等离子体辐照对金属的影响已被广泛研究。辐照温度范围为 430 至 720 K，入射离子能量范围为 30 至 100 eV。通过扫描电子显微镜（SEM）观察发现，锗上出现了各种形态变化，包括凹坑、纳米锥、纳米柱和粗糙表面。通过对扫描电子显微镜显微照片进行快速傅立叶变换，分析了形态变化的空间尺度。热解吸光谱分析表明，在表面温度高于 500 K 时，植入 Ge 的 He 原子在形成粗糙表面的过程中发挥了主要作用。
{"title":"Germanium nanostructures by helium plasma irradiation","authors":"Shin Kajita, Quan Shi, Kiho Tabata, Tatsuya Kuwabara, Hirohiko Tanaka and Noriyasu Ohno","doi":"10.35848/1347-4065/ad5afe","DOIUrl":"https://doi.org/10.35848/1347-4065/ad5afe","url":null,"abstract":"The effects of helium plasma irradiation, which has been widely studied on metals, on germanium have been experimentally investigated. The irradiation temperature ranges from 430 to 720 K, and the incident ion energy ranges from 30 to 100 eV. From the scanning electron microscope (SEM) observation, it was found that various morphological changes including pits, nanocones, nanopillars, and roughened surfaces occur. The spatial scale of the morphological change was analyzed by applying fast Fourier transform to SEM micrographs. Thermal desorption spectroscopy analysis suggests that He atoms implanted on Ge play major roles in forming roughened surfaces at a surface temperature higher than 500 K.","PeriodicalId":14741,"journal":{"name":"Japanese Journal of Applied Physics","volume":"67 1","pages":""},"PeriodicalIF":1.5,"publicationDate":"2024-07-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141773483","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 : 2024-07-22DOI: 10.35848/1347-4065/ad5aff
Marlis N. Agusutrisno, Sora Obinata, Takamasa Okumura, Kunihiro Kamataki, Naho Itagaki, Kazunori Koga, Masaharu Shiratani and Naoto Yamashita
Large-scale fabrication of thulium iron garnet (TmIG) films on gadolinium gallium garnet (GGG) substrates, with a total area of 25 cm2, has been demonstrated by rotating substrate holders during on-axis sputtering. By optimizing the growth parameters based on the pressure and flow rate of the oxygen ratio, a Tm/Fe ratio of 0.65 was obtained, which is close to the stoichiometry of TmIG. The increase in post-annealing temperature has induced the growth of the TmIG structure by the strain of the lattice constant mechanism. At the highest post-annealing temperature, the crystal structure of TmIG (444) and the perpendicular magnetic anisotropy (PMA) were obtained. This result demonstrates the potential method for large-scale fabrication of TmIG film with PMA.
{"title":"Large-scale fabrication of thulium iron garnet film with perpendicular magnetic anisotropy using RF magnetron sputtering","authors":"Marlis N. Agusutrisno, Sora Obinata, Takamasa Okumura, Kunihiro Kamataki, Naho Itagaki, Kazunori Koga, Masaharu Shiratani and Naoto Yamashita","doi":"10.35848/1347-4065/ad5aff","DOIUrl":"https://doi.org/10.35848/1347-4065/ad5aff","url":null,"abstract":"Large-scale fabrication of thulium iron garnet (TmIG) films on gadolinium gallium garnet (GGG) substrates, with a total area of 25 cm2, has been demonstrated by rotating substrate holders during on-axis sputtering. By optimizing the growth parameters based on the pressure and flow rate of the oxygen ratio, a Tm/Fe ratio of 0.65 was obtained, which is close to the stoichiometry of TmIG. The increase in post-annealing temperature has induced the growth of the TmIG structure by the strain of the lattice constant mechanism. At the highest post-annealing temperature, the crystal structure of TmIG (444) and the perpendicular magnetic anisotropy (PMA) were obtained. This result demonstrates the potential method for large-scale fabrication of TmIG film with PMA.","PeriodicalId":14741,"journal":{"name":"Japanese Journal of Applied Physics","volume":"14 1","pages":""},"PeriodicalIF":1.5,"publicationDate":"2024-07-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141773484","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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