Properties and perspectives of ultrawide bandgap Ga2O3 in optoelectronic applications

Gallium oxide (Ga2O3) is an ultrawide bandgap semiconducting material that has been developed for many advanced technology and engineering applications and has potential uses in power devices, optoelectronics and sensing applications because of its high-quality material properties and availability of economically intrinsic substrates. Understanding the properties and applications of Ga2O3 aids in expanding its usage into new fields. This review summarises the crystal structure, polymorphism, thermal properties and optical and optoelectronic device applications of Ga2O3. As a wide bandgap semiconductor, this material has elicited new research interests on the basis of fundamental technologies, leading to various types of applications, including those in the optoelectronic field, such as light-emitting diodes and solar cells. Ga2O3 devices consume less power and have relatively low production cost, making them suitable for mass production. Issues, such as low thermal conductivity and anisotropic crystals in Ga2O3 structures, have been discussed; and suggestions, such as the doping method, have been provided to improve the electrical and optical properties of Ga2O3. The potential, challenges and progress of Ga2O3, particularly as an emerging material for high-power and deep-ultraviolet optoelectronic devices, are also reviewed and presented.