Epitaxial growth of (AlxGa1−x)2O3 thin films on sapphire substrates by plasma assisted pulsed laser deposition

Zewei Chen,Katsuhiko Saito,Tooru Tanaka,Qixin Guo,Makoto Arita

doi:10.1063/5.0046237

Zewei Chen, Katsuhiko Saito + Show 3 more

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https://doi.org/10.1063/5.0046237

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Journal: AIP Advances	Publication Date: Mar 1, 2021
Citations: 12	License type: cc-by

Affiliation: Saga University, Kyushu University

Abstract

(AlxGa1−x)2O3 was grown on a-plane sapphire substrates at 500 °C by plasma assisted pulsed laser deposition (PLD) in the whole Al concentration range. The films were characterized using x-ray photoelectron spectroscopy (XPS), x-ray diffraction, atomic force microscopy, and spectrophotometry. By using XPS to measure the bandgap of the films, it was found that as the Al concentration x changes from 0.00 to 1.00, the bandgap ranges from 5.3 to 8.5 eV. The results show that plasma assisted PLD is a promising method to grow ultra-wide bandgap (AlxGa1−x)2O3 at low temperatures, which paves the way for the application of power devices and other functional devices based on (AlxGa1−x)2O3.

Highlights

INTRODUCTIONΑ-Ga2O3 epilayers have been realized on the sapphire substrate by mist chemical vapor deposition (mist-CVD), metalorganic chemical vapor deposition (MOCVD), pulsed laser deposition (PLD), halide vapor phase epitaxy (HVPE), and molecular beam epitaxy (MBE)
Corundum structured α-Ga2O3, a metastable hexagonal phase of Ga2O3, appertains to the space group of R-3c with the lattice constants a = b = 0.498 nm, c = 1.343 nm, α = β = 90○, and γ = 120○.1 Recently, α-Ga2O3 has received attention for use in radio frequency (RF) devices, high power electronic devices, and optoelectronic devices such as deep ultraviolet solar-blind detectors,2–5 solid-state waveguide lasers,6 ultraviolet transparent conducting oxide (TCO),7 and Schottky barrier diodes (SBDs).8,9 Because of a metastable phase, α-Ga2O3 has not been obtained yet as the bulk material, so it is still impossible to obtain α-Ga2O3 thin films by homoepitaxial methods
Α-Ga2O3 epilayers have been realized on the sapphire substrate by mist chemical vapor deposition,11–13 metalorganic chemical vapor deposition (MOCVD),14 pulsed laser deposition (PLD),15 halide vapor phase epitaxy (HVPE),16 and molecular beam epitaxy (MBE)

Summary

INTRODUCTION

Α-Ga2O3 epilayers have been realized on the sapphire substrate by mist chemical vapor deposition (mist-CVD), metalorganic chemical vapor deposition (MOCVD), pulsed laser deposition (PLD), halide vapor phase epitaxy (HVPE), and molecular beam epitaxy (MBE).. Ito et al have produced corundum structured (AlxGa1−x)2O3 by mist-CVD at 500 ○C and showed that the adjustable bandgap is between 5.30 and 7.80 eV by increasing the Al composition from 0.00 to 0.81.18 Dang et al reported α-(AlxGa1−x)2O3 with Al concentrations from 0.00 to 0.71 grown on sapphire by using the mist-CVD method that shows a tunable bandgap from 5.30 to 7.74 eV.. (AlxGa1−x)2O3 grown on a-plane sapphire by the plasma assisted PLD method has not been investigated. In this work, (AlxGa1−x)2O3 was grown on a-plane sapphire substrates by PLD with the help of plasma. The dependence of the bandgap and structural properties on Al concentrations from 0.00 to 1.00 was discussed

EXPERIMENTAL DETAILS

RESULTS AND DISCUSSION

CONCLUSIONS