Article
Engineering, Electrical & Electronic
Xiongjie Li, Pingjuan Niu, Pingfan Ning, Yong Jiang
Summary: An ultra-flat heteroepitaxy α-Ga2O3 thin film, with a root mean square (RMS) roughness of 0.309 nm and high crystallinity, was successfully obtained on a c-plane sapphire substrate using mist chemical vapor deposition. The growth rate was calculated as 13.22 nm min(-1) and the bandgap of the transparent film was determined to be 5.10 eV. This high quality, wide bandgap heteroepitaxy α-Ga2O3 thin film represents a significant advancement for the preparation of high power and optoelectronic devices.
SEMICONDUCTOR SCIENCE AND TECHNOLOGY
(2023)
Article
Materials Science, Multidisciplinary
Yu Xu, Yaolin Cheng, Zhe Li, Dazheng Chen, Shengrui Xu, Qian Feng, Weidong Zhu, Yachao Zhang, Jincheng Zhang, Chunfu Zhang, Yue Hao
Summary: This study successfully epitaxially grew high-quality beta-Ga2O3 single crystal films on sapphire substrates using a low-cost method and fabricated deep ultraviolet solar-blind photodetectors with excellent photoelectric performance.
ADVANCED MATERIALS TECHNOLOGIES
(2021)
Article
Engineering, Electrical & Electronic
Hiroyuki Nishinaka, Tatsuji Nagaoka, Yuki Kajita, Masahiro Yoshimoto
Summary: Utilizing mist chemical vapor deposition (CVD) process, rapid homoepitaxial growth of beta-Ga2O3 thin films with smooth surfaces was achieved using a concentrated aqueous solution of GaCl3 precursor.
MATERIALS SCIENCE IN SEMICONDUCTOR PROCESSING
(2021)
Article
Materials Science, Multidisciplinary
Armando Hernandez, Md Minhazul Islam, Pooneh Saddatkia, Charles Codding, Prabin Dulal, Sahil Agarwal, Adam Janover, Steven Novak, Mengbing Huang, Tuoc Dang, Mike Snure, F. A. Selim
Summary: Epitaxial Ga2O3 films were grown through MOCVD with optimized growth and doping parameters, showing that electron density and conductivity are influenced by the interplay between dopant concentration, C concentration, and trapping defects in the films. Conductive films with desirable resistivity and mobility for FET and transparent FET applications in DUV technology were successfully obtained.
RESULTS IN PHYSICS
(2021)
Article
Nanoscience & Nanotechnology
A. F. M. Anhar Uddin Bhuiyan, Zixuan Feng, Hsien-Lien Huang, Lingyu Meng, Jinwoo Hwang, Hongping Zhao
Summary: Single alpha-phase (AlxGa1-x)(2)O-3 thin films were successfully grown on m-plane sapphire substrates via metalorganic chemical vapor deposition, demonstrating high quality and uniformity. The influence of growth parameters on film properties was further investigated. X-ray photoelectron spectroscopy was employed to characterize the aluminum content and bandgaps, with the band alignment at heterojunctions also studied.
Article
Chemistry, Analytical
A. Almaev, V. Nikolaev, N. N. Yakovlev, P. N. Butenko, S. Stepanov, A. Pechnikov, M. P. Scheglov, E. Chernikov
Summary: The gas sensing properties of Pt/α-Ga2O3:Sn/Pt metal-semiconductor-metal (MSM) structures based on epitaxial films of α-Ga2O3 with Pt contacts were investigated. The structures showed high sensitivity to H-2, and it was found that the Pt contacts and Sn doping level played a key role in determining the hydrogen sensing properties. The sensitivity to H-2 was attributed to the modulation of the Schottky barrier height between Pt and α-Ga2O3:Sn.
SENSORS AND ACTUATORS B-CHEMICAL
(2022)
Article
Physics, Condensed Matter
Xiaojie Wang, Wenxiang Mu, Jiahui Xie, Jinteng Zhang, Yang Li, Zhitai Jia, Xutang Tao
Summary: In this study, a high-quality 2-inch alpha-Ga2O3 epitaxial film on c-plane sapphire substrates was prepared using the mist-CVD method. The growth rate and phase control mechanisms were investigated. It was found that the growth rate of the alpha-Ga2O3 films was limited by the evaporation of the microdroplets containing gallium acetylacetonate. Phase control was achieved by adjusting the growth temperature. Additionally, the bandgaps and optical transmittance of the alpha-Ga2O3 films grown under different conditions were characterized using UV-visible and near-IR scanning spectra.
JOURNAL OF SEMICONDUCTORS
(2023)
Article
Materials Science, Multidisciplinary
Kazuya Okamura, Ren Saito, Ayaka Kanai, Kunihiko Tanaka
Summary: In this study, Cu2SnS3 (CTS) thin films were prepared using a dual-source fine channel mist CVD method. By adjusting the hot plate temperature and reducing the lift gas flow rate, CTS thin films with suitable morphology for solar cells were obtained without the need for a vacuum apparatus or a sulfurization process.
APPLIED PHYSICS A-MATERIALS SCIENCE & PROCESSING
(2022)
Article
Physics, Applied
A. Y. Polyakov, V. Nikolaev, A. Pechnikov, P. B. Lagov, I. Shchemerov, A. A. Vasilev, A. Chernykh, A. Kochkova, L. Guzilova, Yu S. Pavlov, T. Kulevoy, A. S. Doroshkevich, R. Sh Isaev, A. Panichkin, S. J. Pearton
Summary: Films of alpha-Ga2O3 (Sn) grown on sapphire using halide vapor phase epitaxy with donor densities ranging from 5 x 10(15) to 8.4 x 10(19) cm(-3) were irradiated with 1.1 MeV protons at 25 degrees C. The carrier removal rate for lightly doped samples was 35 cm(-1) at a proton fluence of 10(14) cm(-2) and 1.3 cm(-1) at a proton fluence of 10(15) cm(-2). Deep acceptors with optical ionization energies of 2 eV, 2.8 eV, and 3.1 eV were responsible for the observed removal rate. The electron removal rate for heavily doped samples was similar to that of samples doped at 4 x 10(18) cm(-3). Lightly doped alpha-Ga2O3 films showed higher radiation tolerance compared to similarly doped beta-Ga2O3 layers.
JOURNAL OF PHYSICS D-APPLIED PHYSICS
(2023)
Article
Chemistry, Multidisciplinary
Yan Zuo, Qian Feng, Tao Zhang, Xusheng Tian, Wenji Li, Jiale Li, Chunfu Zhang, Jincheng Zhang, Yue Hao
Summary: This paper investigates the method of growing alpha-Ga2O3 films on c-plane sapphire substrates using an inexpensive fine-channel mist-CVD face-to-face heating plate. By replacing the traditional single-sided heating method with a face-to-face heating method, the requirement for equipment sealability is reduced. Additionally, by optimizing the fabrication conditions, the researchers obtained high-quality alpha-Ga2O3 films with unique surface morphology.
Article
Materials Science, Multidisciplinary
Takahiro Kato, Hiroyuki Nishinaka, Kazuki Shimazoe, Masahiro Yoshimoto
Summary: Epitaxial delta-Ga2O3 thin films were successfully grown on various planes of YSZ and c-plane sapphire substrates by inserting beta-Fe2O3 and bcc-In2O3 buffer layers. The growth involved reducing lattice mismatch and exploring the thermal stability of the buffer layers. Furthermore, the growth of both alpha- and delta-Ga2O3 thin films on c-plane sapphire was achieved using specific buffer layers.
PHYSICA STATUS SOLIDI A-APPLICATIONS AND MATERIALS SCIENCE
(2023)
Article
Chemistry, Multidisciplinary
Ha Young Kang, Habin Kang, Eunhye Lee, Gyeong Ryul Lee, Roy Byung Kyu Chung
Summary: By doping with Sn, the thermal stability of gallium oxide films can be enhanced, especially in the growth of kappa-Ga2O3. Increasing Sn concentration can suppress radiative recombination, although it is not correlated with crystal quality.
Article
Materials Science, Multidisciplinary
Xueqiang Xiang, Li-Heng Li, Chen Chen, Guangwei Xu, Fangzhou Liang, Pengju Tan, Xuanze Zhou, Weibing Hao, Xiaolong Zhao, Haiding Sun, Kan-Hao Xue, Nan Gao, Shibing Long
Summary: In this study, high-quality β-Ga2O3 films were epitaxially grown using MOCVD with different donor concentrations, and their shallow donor states were investigated. The unintentional doping effects were found to have a significant impact on the donor states, and a method to reduce the unintentional doping effect was proposed.
SCIENCE CHINA-MATERIALS
(2023)
Article
Materials Science, Ceramics
Sun-Young Park, Minh-Tan Ha, Kyoung-Ho Kim, Le Van Lich, Yun-Ji Shin, Seong-Min Jeong, Se-Hun Kwon, Si-Young Bae
Summary: This article presents a method for growing smooth surface and high thickness uniformity corundum-structured (alpha-) gallium oxide (Ga2O3) crystalline thin films on sapphire substrates using vertical hot-wall mist chemical vapor deposition (CVD). By tuning the growth variables and microdroplet diameter, optimal surface morphology and growth rate can be achieved. The even flow of mist in the vertical furnace ensures high thickness uniformity of the Ga2O3 epitaxial layer on large-scale substrates.
CERAMICS INTERNATIONAL
(2022)
Article
Nanoscience & Nanotechnology
Mahitosh Biswas, Hiroyuki Nishinaka
Summary: The translation elaborates on the properties and growth of gallium oxide (Ga2O3) and its metastable phases, and discusses their doping and electronic properties. The importance of these phases in power electronics and ultraviolet photodetectors is emphasized.
Article
Physics, Applied
Li Liu, Toshiyuki Kawaharamura, Giang Thai Dang, Ellawala K. C. Pradeep, Shota Sato, Takayuki Uchida, Shizuo Fujita, Takahiro Hiramatsu, Hiroshi Kobayashi, Hiroyuki Orita
JAPANESE JOURNAL OF APPLIED PHYSICS
(2019)
Article
Physics, Applied
Phimolphan Rutthongjan, Li Liu, Misaki Nishi, Masahito Sakamoto, Shota Sato, Ellawala K. C. Pradeep, Giang T. Dang, Toshiyuki Kawaharamura
JAPANESE JOURNAL OF APPLIED PHYSICS
(2019)
Article
Physics, Applied
Phimolphan Rutthongjan, Misaki Nishi, Li Liu, Shota Sato, Yuya Okada, Giang T. Dang, Toshiyuki Kawaharamura
APPLIED PHYSICS EXPRESS
(2019)
Article
Physics, Applied
Giang T. Dang, Martin W. Allen, Mamoru Furuta, Toshiyuki Kawaharamura
JAPANESE JOURNAL OF APPLIED PHYSICS
(2019)
Article
Chemistry, Physical
Daichi Koretomo, Shuhei Hamada, Yusaku Magari, Mamoru Furuta
Article
Chemistry, Multidisciplinary
Dapeng Wang, Mamoru Furuta, Shigekazu Tomai, Koki Yano
Article
Chemistry, Multidisciplinary
Dapeng Wang, Mamoru Furuta, Shigekazu Tomai, Koki Yano
Article
Nanoscience & Nanotechnology
Giang T. Dang, Shota Sato, Yuki Tagashira, Tatsuya Yasuoka, Li Liu, Toshiyuki Kawaharamura
Article
Engineering, Electrical & Electronic
Leila Ghadbeigi, Jacqueline Cooke, Giang T. Dang, Toshiyuki Kawaharamura, Tatsuya Yasuoka, Rujun Sun, Praneeth Ranga, Sriram Krishnamoorthy, Michael A. Scarpulla, Berardi Sensale-Rodriguez
Summary: This study examined the optical properties of thin-film alpha-Ga2O3 synthesized using mist chemical vapor deposition (mist CVD) on double-side polished c-plane sapphire, and compared them with beta-Ga2O3 thin films grown on similar substrates. Despite differences in absorption edge and photoluminescence spectra, both alpha-Ga2O3 and beta-Ga2O3 thin films exhibit similarities in certain features. The varying intensity of photoluminescence bands with excitation photon energy is attributed to a non-uniform defect concentration distribution across the sample depth, with lower defect concentrations associated with blue and green emission in alpha-phase films.
JOURNAL OF ELECTRONIC MATERIALS
(2021)
Article
Nanoscience & Nanotechnology
Tatsuya Yasuoka, Li Liu, Tamako Ozaki, Kanta Asako, Yuna Ishikawa, Miyabi Fukue, Giang T. Dang, Toshiyuki Kawaharamura
Summary: In this study, alpha-Ga2O3 thin films were grown on a c-plane sapphire substrate using a third generation mist chemical vapor deposition system. It was found that HCl has effects on the growth rate, purity, and surface roughness of alpha-Ga2O3 films. By optimizing the HCl/Ga supply ratio and Ga supply rate, the purity of the films was improved.
Article
Physics, Applied
G. T. Dang, T. Yasuoka, T. Kawaharamura
Summary: Utilizing laser interference lithography for sub-micrometer patterning enabled the coalescence growth of alpha-Ga2O3 thin films in a shorter time while maintaining film quality and growth conditions. Transmittance and X-ray diffraction analysis confirmed the dominance of the alpha-phase in the film, with electron microscopy observations validating the growth of alpha-Ga2O3 even on the masking layer.
APPLIED PHYSICS LETTERS
(2021)
Article
Physics, Condensed Matter
Li Liu, Toshiyuki Kawaharamura, Masahito Sakamoto, Misaki Nishi, Giang T. Dang, Shota Sato
Summary: Yttrium oxide (Y2O3) thin films are deposited using a third-generation mist CVD system, with water (H2O) and oxygen (O-2) selected as oxygen sources to support the fabrication process. The use of H2O support results in lower growth temperatures and improved film quality, enhancing the properties of the Y2O3 films. Support processes of H2O and O-2 occur at different times and locations inside the reactor, leading to varying effects on the fabrication process and film properties.
PHYSICA STATUS SOLIDI B-BASIC SOLID STATE PHYSICS
(2021)
Article
Chemistry, Physical
Rostislav Velichko, Yusaku Magari, Mamoru Furuta
Summary: The mechanism for reducing the activation temperature of IGZO:H films was investigated in this paper. In situ Hall measurements and hard X-ray photoelectron spectroscopy analysis revealed that oxygen diffusion during annealing played an important role in reducing oxygen vacancies and subgap states near the Fermi level. Additionally, X-ray reflectometry analysis showed that the density of the IGZO:H film decreased with increasing hydrogen gas flow ratio.
Article
Chemistry, Physical
Taiki Kataoka, Yusaku Magari, Hisao Makino, Mamoru Furuta
Summary: The study demonstrated the conversion of a metallic indium oxide film into a nondegenerate semiconductor indium oxynitride film. By solid-phase crystallization, the Hall mobility was increased and carrier density was reduced, leading to improved field effect mobility in oxide thin film transistors.
Article
Nanoscience & Nanotechnology
Giang T. Dang, Yuki Tagashira, Tatsuya Yasuoka, Li Liu, Toshiyuki Kawaharamura
