 Gallium Oxide GA-203 is an emerging wide bandgap semiconductor that has attracted a large amount of interest due to its ultra-large bandgap of 4.8EV, a high breakdown field of 8MV slash CM, and high thermal stability. This makes it a promising material for a variety of applications such as high power electronic devices and solar blind ultraviolet, UV, photo detectors. In recent years, there have been significant advances in the growth of high-quality bulk crystals and thin films, as well as device optimization for power electronics and solar blind UV detection. Despite these advancements, however, many challenges remain, including difficulties in p-type doping, a large density of unintentional electron carriers and defects slash impurities, and issues with the device process, contact, dielectrics, and surface passivation. The aim of this article is to provide a timely review of the fundamental understanding of the semiconductor physics and chemistry of GA-203, focusing on electronic band structures, optical properties, and chemistry of defects and. This article was authored by Jaya Zhang, Jueli Shur, Dong Chen Qi, and others. We are article.tv, links in the description below.