論文

査読有り
2018年3月7日

Surface and bulk electronic structures of unintentionally and Mg-doped In0.7Ga0.3N epilayer by hard X-ray photoelectron spectroscopy

Journal of Applied Physics
  • Masataka Imura
  • Shunsuke Tsuda
  • Hiroyuki Takeda
  • Takahiro Nagata
  • Ryan G. Banal
  • Hideki Yoshikawa
  • Anli Yang
  • Yoshiyuki Yamashita
  • Keisuke Kobayashi
  • Yasuo Koide
  • Tomohiro Yamaguchi
  • Masamitsu Kaneko
  • Nao Uematsu
  • Ke Wang
  • Tsutomu Araki
  • Yasushi Nanishi
  • 全て表示

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記述言語
英語
掲載種別
研究論文(学術雑誌)
DOI
10.1063/1.5016574
出版者・発行元
American Institute of Physics Inc.

The surface and bulk electronic structures of In0.7Ga0.3N epilayers are investigated by angle-resolved hard X-ray photoelectron spectroscopy (HX-PES) combined with soft X-PES. The unintentionally and Mg-doped In0.7Ga0.3N (u-In0.7Ga0.3N and In0.7Ga0.3N:Mg, respectively) epilayers are grown by radio-frequency plasma-assisted molecular beam epitaxy. Here three samples with different Mg concentrations ([Mg] = 0, 7 × 1019, and 4 × 1020 cm-3) are chosen for comparison. It is found that a large downward energy band bending exists in all samples due to the formation of a surface electron accumulation (SEA) layer. For u-In0.7Ga0.3N epilayer, band bending as large as 0.8 ± 0.05 eV occurs from bulk to surface. Judged from the valence band spectral edge and numerical analysis of energy band with a surface quantum well, the valence band maximum (VBM) with respect to Fermi energy (EF) level in the bulk is determined to be 1.22 ± 0.05 eV. In contrast, for In0.7Ga0.3N:Mg epilayers, the band bending increases and the VBM only in the bulk tends to shift toward the EF level owing to the Mg acceptor doping. Hence, the energy band is considered to exhibit a downward bending structure due to the coexistence of the n+ SEA layer and Mg-doped p layer formed in the bulk. When [Mg] changes from 7 × 1019 to 4 × 1020 cm-3, the peak split occurs in HX-PES spectra under the bulk sensitive condition. This result indicates that the energy band forms an anomalous downward bending structure with a singular point due to the generation of a thin depleted region at the n+ p interface. For In0.7Ga0.3N:Mg epilayers, the VBM in the bulk is assumed to be slightly lower than EF level within 0.1 eV.

リンク情報
DOI
https://doi.org/10.1063/1.5016574
Web of Science
https://gateway.webofknowledge.com/gateway/Gateway.cgi?GWVersion=2&SrcAuth=JSTA_CEL&SrcApp=J_Gate_JST&DestLinkType=FullRecord&KeyUT=WOS:000427104500058&DestApp=WOS_CPL
ID情報
  • DOI : 10.1063/1.5016574
  • ISSN : 1089-7550
  • ISSN : 0021-8979
  • SCOPUS ID : 85042862659
  • Web of Science ID : WOS:000427104500058

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