Band alignment of HfO2/AlN heterojunction investigated by X-ray photoelectron spectroscopy

The band alignment between AlN and Atomic-Layer-Deposited (ALD) HfO2 was determined by X-ray photoelectron spectroscopy(XPS). The shift of Al 2p core-levels to lower binding energies with the decrease of take-off angles θ indicated upward band bending occurred at the AlNsurface. Based on the angle-r...

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Bibliographic Details
Main Authors: Ye, Gang, Wang, Hong, Ji, Rong
Other Authors: School of Electrical and Electronic Engineering
Format: Article
Language:English
Published: 2016
Subjects:
Online Access:https://hdl.handle.net/10356/81515
http://hdl.handle.net/10220/40837
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Institution: Nanyang Technological University
Language: English
Description
Summary:The band alignment between AlN and Atomic-Layer-Deposited (ALD) HfO2 was determined by X-ray photoelectron spectroscopy(XPS). The shift of Al 2p core-levels to lower binding energies with the decrease of take-off angles θ indicated upward band bending occurred at the AlNsurface. Based on the angle-resolved XPS measurements combined with numerical calculations, valence band discontinuity ΔEV of 0.4 ± 0.2 eV at HfO2/AlN interface was determined by taking AlNsurface band bending into account. By taking the band gap of HfO2 and AlN as 5.8 eV and 6.2 eV, respectively, a type-II band line-up was found between HfO2 and AlN.