Ferroelectric-Gated InSe Photodetectors with High On/Off Ratios and Photoresponsivity
Li Liu, Liangmei Wu, Aiwei Wang, Hongtao Liu, Ruisong Ma, Kang Wu, Jiancui Chen, Zhang Zhou, Yuan Tian, Haitao Yang, Chengmin Shen, Lihong Bao, Zhihui Qin, Sokrates T. Pantelides, Hong‐Jun Gao
Abstract
Indium selenide (InSe) has a high electron mobility and tunable direct band gap, enabling its potential applications to electronic and optoelectronic devices. Here, we report the fabrication of InSe photodetectors with high on/off ratios and ultrahigh photoresponsivity, using ferroelectric poly(vinylidene fluoride-trifluoroethylene) (P(VDF-TrFE)) copolymer films as the top-gate dielectric. Benefiting from the successful suppression of the dark current down to ∼10–14A in the InSe channel by tuning the three different polarization states in ferroelectric P(VDF-TrFE) and improved interface properties using h-BN as a substrate, the ferroelectric-gated InSe photodetectors show a high on/off ratio of over 108, a high photoresponsivity up to 14 250 AW–1, a high detectivity up to 1.63 × 1013 Jones, and a fast response time of 600 μs even at zero-gate voltage. The present results highlight the role of ferroelectric P(VDF-TrFE) in tuning the carrier transport of InSe and may provide an avenue for the development of InSe-based photodetectors.