Growth and characterization of β-Ga₂O₃ thin films grown on off-angled Al₂O₃ substrates by metal-organic chemical vapor deposition

Abstract

Beta-gallium oxide (β-Ga2O3) thin films were deposited on c-plane (0001) sapphire substrates with different mis-cut angles along < > by metal-organic chemical vapor deposition (MOCVD). The structural properties and surface morphology of as-grown β-Ga2O3 thin films were investigated in detail. It was found that by using thin buffer layer and mis-cut substrate technology, the full width at half maximum (FWHM) of the ( ) diffraction peak of the β-Ga2O3 film is decreased from 2° on c-plane (0001) Al2O3 substrate to 0.64° on an 8° off-angled c-plane (0001) Al2O3 substrate. The surface root-mean-square (RMS) roughness can also be improved greatly and the value is 1.27 nm for 8° off-angled c-plane (0001) Al2O3 substrate. Room temperature photoluminescence (PL) was observed, which was attributed to the self-trapped excitons formed by oxygen and gallium vacancies in the film. The ultraviolet–blue PL intensity related with oxygen and gallium vacancies is decreased with the increasing mis-cut angle, which is in agreement with the improved crystal quality measured by high resolution X-ray diffraction (HR-XRD). The present results provide a route for growing high quality β-Ga2O3 film on Al2O3 substrate.

High-quality β-(AlxGa1−x)2O3 thin films on sapphire substrates by face-to-face annealing

“…For the as-grown, 1100-1 h, and 1200-1 h samples, three dominant XRD peaks appear for the diffraction on the (−201), (−402), and (−603) planes of β-Ga 2 O 3 . 35 For the as-grown Ga 2 O 3 , its (−201) plane exhibits a diffraction peak at 19.00°, while the standard diffraction peak of the (−201) plane for β-Ga 2 O 3 is usually located at 18.95°. This slight discrepancy between the standard diffraction peak for the (−201) plane and that observed in our study could be attributed to the compressive stress during the hetero-epitaxial growth of Ga 2 O 3 on the sapphire substrate.…”

Two-step growth of β-Ga2O3 on c-plane sapphire using MOCVD for solar-blind photodetector

“…In order to alleviate lattice mismatch and improve crystalline quality of epitaxial films, a buffer layer between substrate and epitaxial layer can be applied. However, there are few reports about the effect of buffer layer on the quality of β-Ga 2 O 3 film on c-sapphire [15,16] .…”

Dual-Schottky-junctions coupling device based on ultra-long β-Ga2O3 single-crystal nanobelt and its photoelectric properties

“…The descent speed of the detector reached 64 ns. Kim et al [21] developed an ozone-treated β-Ga 2 O 3 nanobelt field-effect tube photodetector with a rejection ratio of more than 8 orders of magnitude.…”