Influence of oxygen on the performance of indium titanium zinc oxide UV sensors fabricated via RF sputtering

The authors report the sputtering-based syntheses of five amorphous indium titanium zinc oxide (InTiZnO) UV sensing devices with Ni/Au electrodes. To investigate their UV photodetection performance, the devices were subjected to current-voltage (I-V) characteristic measurements in the dark and under visible light and UV illumination. The oxygen flow ratio played a critical role in the sensing performance of the devices. That is, incorporation of oxygen during RF sputtering may influence the number of oxygen-related defects in the films. All devices exhibited transmittances of over 80% in the visible light region. With an applied bias of 10 V and 290 nm illumination, sample B exhibited a photo-to-dark current ratio of over 104, a UV-to-visible rejection ratio of over 103, and a photoresponsivity of 0.17 A/W.