Band alignment of HfAlO/GaN (0001) determined by X-ray photoelectron spectroscopy : effect of in situ SiH4 passivation
Tan, Leng Seow
Date of Issue2015
School of Electrical and Electronic Engineering
The energy band alignment between HfAlO and GaN (0001) was characterized using high-resolution x-ray photoelectron spectroscopy (XPS). The HfAlO was deposited using a metal-organic chemical vapor deposition (MOCVD) gate cluster. A valence band offset of 0.38 eV and a conduction band offset of 2.22 eV were obtained across the HfAlO/GaN heterointerface without any passivation. With in situ SiH4 passivation (vacuum anneal+SiH4 treatment) on the GaN surface right before HfAlO deposition, the valence band offset and the conduction band offset across the HfAlO/GaN heterointerface were found to be 0.51 eV and 2.09 eV, respectively. The difference in the band alignment is believed to be dominated by the core level up-shift or chemical shift in the GaN substrate as a result of different interlayers (ILs) formed by the two surface preparations.
Journal of alloys and compounds
© 2015 Elsevier B. V. This is the author created version of a work that has been peer reviewed and accepted for publication by Journal of Alloys and Compounds, Elsevier B. V. It incorporates referee’s comments but changes resulting from the publishing process, such as copyediting, structural formatting, may not be reflected in this document. The published version is available at: [Article DOI: http://dx.doi.org/10.1016/j.jallcom.2015.02.139].