Absence of Fermi-level pinning at cleaved nonpolar InN surfaces

Prior experimental work had found that the Fermi level at InN growth surfaces is pinned well above the conduction band edge, leading to strong surface band bending and electron accumulation. Using cross-sectional scanning photoelectron microscopy and spectroscopy, we show definitive evidence of unpi...

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Veröffentlicht in:Physical review letters 2008-09, Vol.101 (10), p.106803-106803, Article 106803
Hauptverfasser: Wu, Chung-Lin, Lee, Hong-Mao, Kuo, Cheng-Tai, Chen, Chia-Hao, Gwo, Shangjr
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Sprache:eng
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Zusammenfassung:Prior experimental work had found that the Fermi level at InN growth surfaces is pinned well above the conduction band edge, leading to strong surface band bending and electron accumulation. Using cross-sectional scanning photoelectron microscopy and spectroscopy, we show definitive evidence of unpinned Fermi level for in situ cleaved a-plane InN surfaces. To confirm the presence or absence of band bending, the surface Fermi level relative to the valence band edge was precisely measured by using both the Fermi edge of Au reference sample and the core level of ultrathin Au overlayer. It is confirmed that flat surface bands only occur at cleaved nonpolar surfaces, consistent with the recent theoretical predictions.
ISSN:0031-9007
1079-7114
DOI:10.1103/physrevlett.101.106803