Valence and conduction band offsets of β-Ga2O3/AlN heterojunction
Torres Castanedo, C. G.
KAUST DepartmentComputer, Electrical and Mathematical Sciences and Engineering (CEMSE) Division
Physical Sciences and Engineering (PSE) Division
Materials Science and Engineering Program
Electrical Engineering Program
King Abdullah University of Science and Technology (KAUST), Advanced Semiconductor Laboratory, Thuwal 23955-6900, Saudi Arabia
KAUST Grant NumberBAS/1/1664-01-01
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AbstractBoth 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.
CitationSun H, Torres Castanedo CG, Liu K, Li K-H, Guo W, et al. (2017) Valence and conduction band offsets of β-Ga2O3/AlN heterojunction. Applied Physics Letters 111: 162105. Available: http://dx.doi.org/10.1063/1.5003930.
SponsorsThe 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.
JournalApplied Physics Letters