Amorphous InGaZnO Ultraviolet Phototransistors With a Thin Ga2O3 Layer

The authors report the fabrication of amorphous IGZO (a-IGZO) phototransistors with a thin Ga2O3layer. It was found that the performances of the phototransistors depend strongly on the oxygen partial pressure during the deposition of the Ga2O3layer. It was also found that the fabricated devices exhibited good electrical properties with electron mobility (μFE) of 13.2 cm2/V·s, subthreshold swing (SS) of 0.13 V/decade, and ON/OFF current ratio> 5 × 105. Furthermore, it was found that two cutoffs exist in the devices prepared with 25% oxygen partial pressure. The deep-ultraviolet (UV)-to-visible rejection ratio and near-UV-to-visible rejection ratio of the fabricated phototransistors were 104and 20, respectively.