Band alignment of p-type oxide/ε-Ga2O3 heterojunctions investigated by x-ray photoelectron spectroscopy
- 1 August 2020
- journal article
- research article
- Published by IOP Publishing in Chinese Physics B
- Vol. 29 (9), 097303
- https://doi.org/10.1088/1674-1056/ab9c0d
Abstract
The epsilon-Ga(2)O(3)p-n heterojunctions (HJ) have been demonstrated using typical p-type oxide semiconductors (NiO or SnO). The epsilon-Ga(2)O(3)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 epsilon-Ga(2)O(3)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/epsilon-Ga(2)O(3)and 1.7 eV at NiO/epsilon-Ga2O3. Considering the bandgaps determined by ultraviolet-visible spectroscopy, the conduction band offsets (CBO) of 0.11 eV at SnO/epsilon-Ga(2)O(3)and 0.44 eV at NiO/epsilon-Ga(2)O(3)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 epsilon-Ga(2)O(3)p-n HJ interface, and design optoelectronic devices based on epsilon-Ga(2)O(3)with novel functionality and improved performance.This publication has 31 references indexed in Scilit:
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