TY - JOUR
T1 - Valence and conduction band offsets of β-Ga2O3/AlN heterojunction
AU - Sun, Haiding
AU - Torres Castanedo, C. G.
AU - Liu, Kaikai
AU - Li, Kuang-Hui
AU - Guo, Wenzhe
AU - Lin, Ronghui
AU - Liu, Xinwei
AU - Li, Jingtao
AU - Li, Xiaohang
N1 - KAUST Repository Item: Exported on 2020-10-01
Acknowledged KAUST grant number(s): BAS/1/1664-01-01
Acknowledgements: The KAUST authors would like to acknowledge the support of Baseline BAS/1/1664-01-01 and Professor Russell D. Dupuis from the Georgia Institute of Technology for supplying the AlN/sapphire template.
PY - 2017/10/16
Y1 - 2017/10/16
N2 - Both β-Ga2O3 and wurtzite AlN have wide bandgaps of 4.5–4.9 and 6.1 eV, respectively. We calculated the in-plane lattice mismatch between the (−201) plane of β-Ga2O3 and the (0002) plane of AlN, which was found to be 2.4%. This is the smallest mismatch between β-Ga2O3 and binary III-nitrides which is beneficial for the formation of a high quality β-Ga2O3/AlN heterojunction. However, the valence and conduction band offsets (VBO and CBO) at the β-Ga2O3/AlN heterojunction have not yet been identified. In this study, a very thin (less than 2 nm) β-Ga2O3 layer was deposited on an AlN/sapphire template to form the heterojunction by pulsed laser deposition. High-resolution X-ray photoelectron spectroscopy revealed the core-level (CL) binding energies of Ga 3d and Al 2p with respect to the valence band maximum in individual β-Ga2O3 and AlN layers, respectively. The separation between Ga 3d and Al 2p CLs at the β-Ga2O3/AlN interface was also measured. Eventually, the VBO was found to be −0.55 ± 0.05 eV. Consequently, a staggered-gap (type II) heterojunction with a CBO of −1.75 ± 0.05 eV was determined. The identification of the band alignment of the β-Ga2O3/AlN heterojunction could facilitate the design of optical and electronic devices based on these and related alloys.
AB - Both β-Ga2O3 and wurtzite AlN have wide bandgaps of 4.5–4.9 and 6.1 eV, respectively. We calculated the in-plane lattice mismatch between the (−201) plane of β-Ga2O3 and the (0002) plane of AlN, which was found to be 2.4%. This is the smallest mismatch between β-Ga2O3 and binary III-nitrides which is beneficial for the formation of a high quality β-Ga2O3/AlN heterojunction. However, the valence and conduction band offsets (VBO and CBO) at the β-Ga2O3/AlN heterojunction have not yet been identified. In this study, a very thin (less than 2 nm) β-Ga2O3 layer was deposited on an AlN/sapphire template to form the heterojunction by pulsed laser deposition. High-resolution X-ray photoelectron spectroscopy revealed the core-level (CL) binding energies of Ga 3d and Al 2p with respect to the valence band maximum in individual β-Ga2O3 and AlN layers, respectively. The separation between Ga 3d and Al 2p CLs at the β-Ga2O3/AlN interface was also measured. Eventually, the VBO was found to be −0.55 ± 0.05 eV. Consequently, a staggered-gap (type II) heterojunction with a CBO of −1.75 ± 0.05 eV was determined. The identification of the band alignment of the β-Ga2O3/AlN heterojunction could facilitate the design of optical and electronic devices based on these and related alloys.
UR - http://hdl.handle.net/10754/625877
UR - http://aip.scitation.org/doi/10.1063/1.5003930
UR - http://www.scopus.com/inward/record.url?scp=85031717371&partnerID=8YFLogxK
U2 - 10.1063/1.5003930
DO - 10.1063/1.5003930
M3 - Article
SN - 0003-6951
VL - 111
SP - 162105
JO - Applied Physics Letters
JF - Applied Physics Letters
IS - 16
ER -