Energy-band engineering and deep-ultraviolet photodetection of Ga₂O₃ alloys: a concise review

Gallium oxide (Ga₂O₃)-based solar-blind ultraviolet photodetectors gained much attention for their promising prospects in new-generation solid-state optoelectronics and electronics. Catering for the demands of broadband photodetection, tunable energy-band, adjusted carrier concentration and effective carrier transition, alloying engineering through doping is gradually launched as one of the research emphases. This review is proposed to understand the photodetection performances in view of energy-band engineering. Especially for the representative (In<i>_x</i>Ga_1-<i>x</i>)₂O₃and (Al<i>_y</i>Ga_1-<i>y</i>)₂O₃alloys, the conduction band edges upshift as the empty Al 3 s and In 5 s states are introduced with higher energy, hybridize with Ga 4 s state. This leads to a result that low effective electron mass and high electron mobility could be achieved, contributing to high quality tunable performances of solar-blind UV photodetection. Thus, in this concise review article, the alloyed Ga₂O₃for photodetection would be reviewed and discussed based on the current developments, from the viewpoint of energy-band theory.