Fabrication and interface properties of amorphous Ga2O3/GaAs heterojunction

Abstract

Heterojunctions based on the combination of wide and narrow bandgap materials provide a basis for realizing high-performance electronic and optoelectronic devices. So, it is crucial to study the interface properties of heterojunctions. Inspired by this idea, an ultra-wide bandgap Ga2O3 film was grown on a narrow bandgap GaAs by atomic layer deposition (ALD) in this work. The morphology was analyzed by atomic force microscope (AFM), showing an excellent uniformity of the film. The thickness of Ga2O3 film was estimated to be 80 nm by Ellipsometry, and its unique adsorption in the solar blind wavelength range was also investigated. X‐ray photoelectron spectroscopy (XPS) was used to characterize the band alignment, and elememtal composition. The value of the valence band offset was 3.15 ± 0.04 eV, and the conduction band offset was 0.25 ± 0.02 eV. The work functions of Ga2O3, and GaAs were calculated by first principles based on density functional theory (DFT), building the carrier immigration mode at the interface of Ga2O3/GaAs heterojunction combined with the band alignment. The band configurations of Ga2O3/GaAs heterojunction illustrate the possibility of realizing high-speed photodetectors. Furthermore, the band offset provides the reference value of barrier height, facilitating the design of electronic and optoelectronic devices based on this heterojunction.