Gallium oxide, and in particular its thermodynamically stable β-Ga2O3 phase, is within the most exciting materials in research and technology nowadays due to its unique properties. The very high breakdown electric field and the figure of merit rivaled only by diamond have tremendous potential for the next generation “green” electronics enabling efficient distribution, use, and conversion of electrical energy. Ion implantation is a traditional technological method used in these fields, and its well-known advantages can contribute greatly to the rapid development of physics and technology of Ga2O3-based materials and devices. Here, the status of ion implantation in β-Ga2O3 nowadays is reviewed. Attention is mainly paid to the results of experimental study of damage under ion irradiation and the properties of Ga2O3 layers doped by ion implantation. The results of ab initio theoretical calculations of the impurities and defect parameters are briefly presented, and the physical principles of a number of analytical methods used to study implanted gallium oxide layers are highlighted. The use of ion implantation in the development of Ga2O3-based devices, such as metal oxide field-effect transistors, Schottky barrier diodes, and solar-blind UV detectors, is described together with systematical analysis of the achieved values of their characteristics. Finally, the most important challenges to be overcome in this field of science and technology are discussed.

The MSM structures based on high-quality 1.6 μm in thick α-Ga ₂ O ₃ films grown by the halide vapor phase epitaxy with Ti/Ni interdigital contacts were developed for detection of short-wave ultraviolet (UVC) radiation. The spectral dependences of responsivity, external quantum efficiency and detectivity of MSM structures based on α-Ga ₂ O ₃ were studied in the wavelength range of 205-260 nm. The responsivity, the external quantum efficiency and the detectivity are 7.19×10 ⁴ A×W ^-1 , 3.79×10 ⁵ arb.un. and 1.12×10 ¹⁸ Hz ^0.5 ×cm×W ^-1 , respectively, for structures with an interelectrode distance of 30 μm at an applied voltage of 10 V and exposure to radiation with a wavelength of 235 nm. The high values of the photoelectric characteristics were caused by the manifestation of an internal gain of the photoresponse due to the self-localization of holes in α-Ga ₂ O ₃ . The prospects of researches to develop UVC radiation detectors for wireless UVC communication were shown.

High-temperature β-Ga2O3:Cr2O3-based sensors sensitive to oxygen- and hydrogen-containing gases have been developed and studied. Magnetron cosputtering is the method of choice for the thin film synthesis as an industry-compatible technique. The composition-structure-properties relationship has been revealed. An introduction of 0.04–0.14 wt. % Cr leads to a significant increase in the response of the O2 sensors over the temperature range 250–400 °C. The highest response in the above-mentioned temperature range has been achieved for a Cr addition of 0.14 wt. %. An increase in the Cr content from 0.04 to 0.22 wt. % leads to a decrease in the β-Ga2O3-based sensors’ response time, especially for low O2 concentrations (≤10 vol. %). Reliable control of the β-Ga2O3:Cr2O3-based sensors’ selectivity to industry-relevant reducing gases—hydrogen, carbon monoxide, and toluene—is demonstrated. β-Ga2O3 films with a Cr incorporation content of 0.04 and 0.06 wt. % have a high response to toluene at operating temperatures 300–500 °C, while the films with 0.14 and 0.22 wt. % Cr have a high response to H2 in the range 400–500 °C. Regardless of the Cr content in β-Ga2O3 thin films, all sensors considered demonstrate a weak response to CO within the operating temperature range 250–500 °C. The results attained are of certain technological importance, i.e., in terms of the development of cost-effective methods for the synthesis of materials and systems for monitoring and control of industry-relevant gases for an environmentally friendly and sustainable growth.