Bandgap-Engineered in Indium–Gallium–Oxide Ultraviolet Phototransistors

The electrical performance of amorphous indium gallium oxide (a-IGO) thin-film transistors applied as deep-ultraviolet (DUV) phototransistors is investigated. It was found that the bandgap of a-IGO can be engineered by altering its chemical composition. The performance of the phototransistors depended strongly on In ₂ O ₃ content in the IGO film. When the indium content increases from 21% to 31%, the phototransistor cutoff red-shifted from 280 to 320 nm. The DUV-to-visible rejection ratio and photoresponsivity of the fabricated phototransistors were ~10 ⁵ and 0.18 A/W.