Mechanically Exfoliated Few-Layer SnS<sub>2</sub> and Integrated van der Waals Electrodes for Ultrahigh Responsivity Phototransistors
Fobao Huang, Jianghua Chen, Chunyang Du, Qiao Zhang, Yiluo Ding, Wei Huang
Abstract
SnS2 presents a high absorption coefficient and intense photoconductivity in the ultraviolet–visible region, rendering it a promising photosensitive material with outstanding optoelectronic properties. Most of the channel materials for SnS2 phototransistors are prepared by chemical vapor deposition (CVD), and the electrodes are prepared by thermal evaporation. However, the CVD procedure is more complicated, and the preparation cycle is long; also, the thermally evaporated electrodes tend to introduce defects at the device interface. Herein, we report an ultra-high-responsivity few-layer SnS2-based phototransistor of which the channel material was prepared by mechanically exfoliating, and the contact gold electrodes were transferred using a dry transfer technique. Under 532 nm illumination, it exhibits an ultrahigh responsivity of 1301 A/W and an ultralow dark current of 1.85 pA with the gate voltage modulated, while having a specific detectivity of 3.20 × 1012 Jones and millisecond-scale response times comparable to those of other devices of this type. Such a high-response phototransistor is promising to promote the research on the performance enhancement of two-dimensional material photodetectors and their application in the field of optoelectronics.