Band Offsets of the MOCVD-Grown β-(Al0.21Ga0.79)2O3/β-Ga2O3 (010) Heterojunction

Timothy A Morgan; Justin Rudie; Mohammad Zamani-Alavijeh; Andrian V Kuchuk; Nazar Orishchin; Fikadu Alema; Andrei Osinsky; Robert Sleezer; Gregory Salamo; Morgan E Ware

doi:10.1021/acsami.2c04177

Band Offsets of the MOCVD-Grown β-(Al_0.21Ga_0.79)₂O₃/β-Ga₂O₃ (010) Heterojunction

ACS Appl Mater Interfaces. 2022 Jul 18. doi: 10.1021/acsami.2c04177. Online ahead of print.

Authors

Timothy A Morgan^{1

2}, Justin Rudie¹, Mohammad Zamani-Alavijeh^{1

3}, Andrian V Kuchuk¹, Nazar Orishchin⁴, Fikadu Alema⁴, Andrei Osinsky⁴, Robert Sleezer⁵, Gregory Salamo¹, Morgan E Ware^{1

6}

Affiliations

¹ Institute for Nanoscience and Engineering, University of Arkansas, 731 W Dickson Street, Fayetteville, Arkansas 72701, United States.
² Naval Surface Warfare Center Crane, 300 HWY 361, Crane, Indiana 47522, United States.
³ Physics Department, University of Arkansas, 835 W Dickson Street, Fayetteville, Arkansas 72701, United States.
⁴ Agnitron Technology Incorporated, Chanhassen, Minnesota 55317, United States.
⁵ Twin Cities Engineering, Minnesota State University, Mankato, 9700 France Avenue, Suite P0820, Bloomington, Minnesota 55431, United States.
⁶ Department of Electrical Engineering, University of Arkansas, 4183 Bell Engineering Center, Fayetteville, Arkansas 72701, United States.

PMID: 35848769
DOI: 10.1021/acsami.2c04177

Abstract

The band offsets for the β-(Al_0.21Ga_0.79)₂O₃/β-Ga₂O₃ (010) heterojunction have been experimentally measured by X-ray photoelectron spectroscopy. High-quality β-(Al_0.21Ga_0.79)₂O₃ films were grown by metal-organic chemical vapor deposition for characterization. The indirect band gap of β-(Al_0.21Ga_0.79)₂O₃ was determined by optical transmission to be 4.69 ± 0.03 eV with a direct transition of 5.37 ± 0.03 eV, while β-Ga₂O₃ was confirmed to have an indirect band gap of 4.52 ± 0.03 eV with a direct transition of 4.94 ± 0.03 eV. The resulting band alignment at the heterojunction was determined to be of type II with the valence and conduction band edges of β-(Al_0.21Ga_0.79)₂O₃ being -0.26 ± 0.08 and 0.43 ± 0.08 eV, respectively, above those of β-Ga₂O₃ (010). These values can now be used to help better design and predict the performance of β-(Al_xGa_1-x)₂O₃ heterojunction-based devices.

Keywords: Tauc plots; X-ray photoelectron spectroscopy (XPS); band offset; heterostructure; metal−organic chemical vapor deposition (MOCVD); β-aluminum gallium oxide.