Gallium oxide (Ga ₂ O ₃ ) is rapidly emerging as a material of choice for the development of solar blind photodetectors and power electronic devices which are particularly suitable in harsh environment applications, owing to its wide bandgap and extremely high Baliga figure of merit. The Ga ₂ O ₃ based devices show robustness against chemical, thermal and radiation environments. Unfortunately, the current Ga ₂ O ₃ technology is still not mature for commercial usage. Thus, extensive research on the growth of various polymorph of Ga ₂ O ₃ materials has been carried out. This article aims to provide an overview of the current understanding of epitaxial growth of different phases of Ga ₂ O ₃ by various growth techniques including pulsed laser deposition, molecular beam epitaxy, metal-organic chemical vapor deposition, sputtering, mist chemical vapor deposition and atomic layer deposition. The review also investigates the factors such as the growth temperature, pressure, carrier gas, III/V ratio, substrate as well as doping which would influence the synthesis and the stability of meta stable phases of Ga ₂ O ₃ . In addition, a thorough discussion of growth window is also provided using phase diagrams for aforementioned epitaxial deposition methods.

High-temperature operation of metal–semiconductor–metal (MSM) UV photodetectors fabricated on pulsed laser deposited β-Ga₂O₃ thin films has been investigated. These photodetectors were operated up to 250 °C temperature under 255 nm illumination. The photo to dark current ratio of about 7100 was observed at room temperature and 2.3 at a high temperature of 250 °C with 10 V applied bias. A decline in photocurrent was observed until a temperature of 150 °C beyond which it increased with temperature up to 250 °C. The suppression of the UV and blue band was also observed in the normalized spectral response curve above 150 °C temperature. Temperature-dependent rise and decay times of temporal response were analyzed to understand the associated photocurrent mechanism at high temperatures. Electron–phonon interaction and self-trapped holes were found to influence the photoresponse in the devices. The obtained results are encouraging and significant for high-temperature applications of β-Ga₂O₃ MSM deep UV photodetectors.

The electrical device characteristics of Ni/β-Ga₂O₃ vertical Schottky barrier diodes (SBDs) were measured in situ during the irradiation of 120 MeV Ag⁷⁺ swift heavy ions (SHIs). These devices exhibit SHI irradiation-induced degradation with 120 MeV Ag⁷⁺ ions in the ion fluence ranges of 1 × 10¹⁰ to 1 × 10¹² ions/cm². The height of the Schottky barrier is found to decrease from 1.11 to 0.93 eV, and the ideality factor increases from 1.16 to 2.06. These changes indicate the degradation of the device with SHI irradiation. A significant four orders increase is observed in the leakage current density from 4.04 × 10⁻⁸ to 1.98 × 10⁻⁴ A/cm² at −1 V, and the series resistance also increases from 3.38 × 10³ to 1.15 × 10⁴ Ω. X-ray photoelectron spectroscopy measurements show that the Ga ions are present in divalent and trivalent states with the spectral features having the binding energies centered at 20.2 eV and 19.9 eV (Ga 3d core-levels) before and after ion irradiation. The O 2s peak shifts to 23.7 eV, and there is an increase in intensity and peak broadening due to the change in the trivalent to divalent state of Ga due to the irradiation. The O(I) peak appears at 530.7 eV in the pristine sample with the Ga–O bonding with the Ga³⁺ state in pure Ga₂O₃. Moreover, there is a significant change in the intensity and the peak width of O(II) centered at 533.0 eV after ion irradiation at the fluence of 1 × 10¹² ions/cm². This indicates that there is an increase in the surface adsorbed/lattice oxygen, resulting in GaO.