High Responsivity MgZnO Ultraviolet Thin-Film Phototransistor Developed Using Radio Frequency Sputtering

• Main Authors: Jyun-Yi Li, Sheng-Po Chang, Ming-Hung Hsu, Shoou-Jinn Chang
• Format: Article
• Language: English
• Published: MDPI AG 2017-02-01
• Series: Materials
• Subjects: magnesium zinc oxide; ultraviolet; thin-film transistor; phototransistor
• Online Access: http://www.mdpi.com/1996-1944/10/2/126

We investigated the electrical and optoelectronic properties of a magnesium zinc oxide thin-film phototransistor. We fabricate an ultraviolet phototransistor by using a wide-bandgap MgZnO thin film as the active layer material of the thin film transistor (TFT). The fabricated device demonstrated a threshold voltage of 3.1 V, on–off current ratio of 105, subthreshold swing of 0.8 V/decade, and mobility of 5 cm2/V·s in a dark environment. As a UV photodetector, the responsivity of the device was 3.12 A/W, and the rejection ratio was 6.55 × 105 at a gate bias of −5 V under 290 nm illumination.