2021年5月6日
Band Bending of n-GaN under Ambient H2O Vapor Studied by X-ray Photoelectron Spectroscopy
The Journal of Physical Chemistry C
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- 巻
- 125
- 号
- 17
- 開始ページ
- 9011
- 終了ページ
- 9019
- 記述言語
- 英語
- 掲載種別
- 研究論文(学術雑誌)
- DOI
- 10.1021/acs.jpcc.0c11174
- 出版者・発行元
- American Chemical Society (ACS)
To improve the performance of semiconductor photoelectrodes for water splitting, the amount of band bending in the depletion layer of a semiconductor should be accurately ascertained, since it determines the splitting efficiency of photo-generated carriers. Band bending has been determined by X-ray photoelectron spectroscopy (XPS) from the valence band maximum (VBM), which has been calculated from the Ga 3d peak using the energy difference between VBM and Ga 3d (Delta EVBM-3d). This work validates several values for Delta EVBM-3d which have been reported previously, by analyzing the spectrum around the VBM and its distance from Ga 3d for the n-GaN(0001) surface under both ultrahigh vacuum (UHV) and ambient H2O center dot Delta EVBM-3d is estimated to be between 17.36 and 17.55 eV. By adopting 17.5 eV as Delta EVBM-3d, the amounts of band-bending were 0.5 eV under UHV and 0.1 eV under a relative humidity of 46%, respectively. For the latter condition, a surface photovoltage of 20 meV was observed upon Xe lamp irradiation, confirming the existence of band bending even with H2O adsorption on the surface. The origin of such band bending seems to be Fermi level pinning to the subsurface states which cannot be compensated by H2O.
- リンク情報
- ID情報
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- DOI : 10.1021/acs.jpcc.0c11174
- ISSN : 1932-7447
- eISSN : 1932-7455
- Web of Science ID : WOS:000648873500010