Ultrasensitive Phototransistors Based on Few-Layered HfS2.

Xu, Kai; Wang, Zhenxing; Wang, Feng; Huang, Yun; Wang, Fengmei; Yin, Lei; Jiang, Chao; He, Jun · Adv Mater · 2015

basic_science · Level V

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Abstract

An ultrathin HfS2 -based ultrasensitive phototransistor is systematically studied. Au-contacted HfS2 phototransistors with ideal thickness ranging from 7 to 12 nm exhibit a high on/off ratio of ca. 10(7) , ultrahigh photoresponsivity over 890 A W(-1) , and photogain over 2300. Moreover, the response time is strongly dependent on the back-gate voltage and shows a reverse trend for Au and Cr metals.