Low-voltage ultraviolet detectors using ZnO thin-film transistor isolated by B ion implantation

Abstract

We report on the fabrication of a photo-detector and a photo-inverter adopting ZnO thin-film transistors (TFTs) that have been electrically isolated by implanting B ions onto peripheral ZnO area around active ZnO channel. Our isolated ZnO-TFT exhibited a fine mobility of 0.8cm(2)/(V.s) and on/off current ratio of similar to 10(4). Since the device also showed quite a high threshold voltage of 21 V, it was effective to be a photo-detector under a zero gate bias. When our photo-devices were composed of a ZnO-TFT and a 100M Omega resistor, a minimum response time of similar to 5 ms under 364nm ultraviolet light was achieved, thereby dynamically showing photo-inverting and detecting behaviors.