中国物理B ›› 2020, Vol. 29 ›› Issue (9): 97303-097303.doi: 10.1088/1674-1056/ab9c0d

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Band alignment of p-type oxide/ε-Ga2O3 heterojunctions investigated by x-ray photoelectron spectroscopy

Chang Rao(饶畅), Zeyuan Fei(费泽元), Weiqu Chen(陈伟驱), Zimin Chen(陈梓敏), Xing Lu(卢星), Gang Wang(王钢), Xinzhong Wang(王新中), Jun Liang(梁军), Yanli Pei(裴艳丽)   

  1. 1 School of Electronics and Information Technology, State Key Laboratory of Optoelectronics Materials & Technologies, Sun Yat-Sen University, Guangzhou 510006, China;
    2 Department of Electronic Communication and Technology, Shenzhen Institute of Information Technology, Shenzhen 518172, China;
    3 School of Advance Materials, Peking University Shenzhen Graduated School, Shenzhen 518055, China
  • 收稿日期:2020-03-25 修回日期:2020-05-27 接受日期:2020-06-12 出版日期:2020-09-05 发布日期:2020-09-05
  • 通讯作者: Yanli Pei E-mail:peiyanli@mail.sysu.edu.cn
  • 基金资助:
    Project supported by the National Natural Science Foundation of China (Grant No. 61774172), the Guangdong Provincial Department of Science and Technology, China (Grant Nos. 2019B010132002 and 2016B090918106), the Pengcheng Scholar Funding (2018), and Shenzhen Science and Technology Innovation Committee, China (Grant No. KQJSCX20180323174713505).

Band alignment of p-type oxide/ε-Ga2O3 heterojunctions investigated by x-ray photoelectron spectroscopy

Chang Rao(饶畅)1, Zeyuan Fei(费泽元)1, Weiqu Chen(陈伟驱)1, Zimin Chen(陈梓敏)1, Xing Lu(卢星)1, Gang Wang(王钢)1, Xinzhong Wang(王新中)2, Jun Liang(梁军)3, Yanli Pei(裴艳丽)1,2   

  1. 1 School of Electronics and Information Technology, State Key Laboratory of Optoelectronics Materials & Technologies, Sun Yat-Sen University, Guangzhou 510006, China;
    2 Department of Electronic Communication and Technology, Shenzhen Institute of Information Technology, Shenzhen 518172, China;
    3 School of Advance Materials, Peking University Shenzhen Graduated School, Shenzhen 518055, China
  • Received:2020-03-25 Revised:2020-05-27 Accepted:2020-06-12 Online:2020-09-05 Published:2020-09-05
  • Contact: Yanli Pei E-mail:peiyanli@mail.sysu.edu.cn
  • Supported by:
    Project supported by the National Natural Science Foundation of China (Grant No. 61774172), the Guangdong Provincial Department of Science and Technology, China (Grant Nos. 2019B010132002 and 2016B090918106), the Pengcheng Scholar Funding (2018), and Shenzhen Science and Technology Innovation Committee, China (Grant No. KQJSCX20180323174713505).

摘要: The ε-Ga2O3 p-n heterojunctions (HJ) have been demonstrated using typical p-type oxide semiconductors (NiO or SnO). The ε-Ga2O3 thin film was heteroepitaxial grown by metal organic chemical vapor deposition (MOCVD) with three-step growth method. The polycrystalline SnO and NiO thin films were deposited on the ε-Ga2O3 thin film by electron-beam evaporation and thermal oxidation, respectively. The valence band offsets (VBO) were determined by x-ray photoelectron spectroscopy (XPS) to be 2.17 eV at SnO/ε-Ga2O3 and 1.7 eV at NiO/ε-Ga2O3. Considering the bandgaps determined by ultraviolet-visible spectroscopy, the conduction band offsets (CBO) of 0.11 eV at SnO/ε-Ga2O3 and 0.44 eV at NiO/ε-Ga2O3 were obtained. The type-Ⅱ band diagrams have been drawn for both p-n HJs. The results are useful to understand the electronic structures at the ε-Ga2O3 p-n HJ interface, and design optoelectronic devices based on ε-Ga2O3 with novel functionality and improved performance.

关键词: ε-Ga2O3, x-ray photoelectron spectroscopy (XPS), valence band offset, band alignment

Abstract: The ε-Ga2O3 p-n heterojunctions (HJ) have been demonstrated using typical p-type oxide semiconductors (NiO or SnO). The ε-Ga2O3 thin film was heteroepitaxial grown by metal organic chemical vapor deposition (MOCVD) with three-step growth method. The polycrystalline SnO and NiO thin films were deposited on the ε-Ga2O3 thin film by electron-beam evaporation and thermal oxidation, respectively. The valence band offsets (VBO) were determined by x-ray photoelectron spectroscopy (XPS) to be 2.17 eV at SnO/ε-Ga2O3 and 1.7 eV at NiO/ε-Ga2O3. Considering the bandgaps determined by ultraviolet-visible spectroscopy, the conduction band offsets (CBO) of 0.11 eV at SnO/ε-Ga2O3 and 0.44 eV at NiO/ε-Ga2O3 were obtained. The type-Ⅱ band diagrams have been drawn for both p-n HJs. The results are useful to understand the electronic structures at the ε-Ga2O3 p-n HJ interface, and design optoelectronic devices based on ε-Ga2O3 with novel functionality and improved performance.

Key words: ε-Ga2O3, x-ray photoelectron spectroscopy (XPS), valence band offset, band alignment

中图分类号:  (Other semiconductor-to-semiconductor contacts, p-n junctions, and heterojunctions)

  • 73.40.Lq
82.80.Pv (Electron spectroscopy (X-ray photoelectron (XPS), Auger electron spectroscopy (AES), etc.)) 73.20.At (Surface states, band structure, electron density of states) 73.61.Le (Other inorganic semiconductors)