American Chemical Society
nn405037s_si_001.pdf (3.2 MB)
Download file

Extraordinary Photoresponse in Two-Dimensional In2Se3 Nanosheets

Download (3.2 MB)
journal contribution
posted on 2014-01-28, 00:00 authored by Robin B. Jacobs-Gedrim, Mariyappan Shanmugam, Nikhil Jain, Christopher A. Durcan, Michael T. Murphy, Thomas M. Murray, Richard J. Matyi, Richard L. Moore, Bin Yu
We demonstrate extraordinary photoconductive behavior in two-dimensional (2D) crystalline indium selenide (In2Se3) nanosheets. Photocurrent measurements reveal that semiconducting In2Se3 nanosheets have an extremely high response to visible light, exhibiting a photoresponsivity of 3.95 × 102 A·W–1 at 300 nm with an external quantum efficiency greater than 1.63 × 105 % at 5 V bias. The key figures-of-merit exceed that of graphene and other 2D material-based photodetectors reported to date. In addition, the photodetector has a fast response time of 1.8 × 10–2 s and a specific detectivity of 2.26 × 1012 Jones. The photoconductive response of α-In2Se3 nanosheets extends into ultraviolet, visible, and near-infrared spectral regions. The high photocurrent response is attributed to the direct band gap (EG = 1.3 eV) of In2Se3 combined with a large surface-area-to-volume ratio and a self-terminated/native-oxide-free surface, which help to reduce carrier recombination while keeping fast response, allowing for real-time detection under very low-light conditions.