High-Performance Ultrabroadband Monocrystalline Tin Monosulfide/Silicon Heterojunction Photodetectors for Multifunctional Optoelectronic Applications.

Developing photodetectors simultaneously exhibiting low energy consumption, suppressed noise, high sensitivity, and broad spectral range has been a long-standing challenge in the optoelectronics field. In this work, high-quality monocrystalline SnS (m-SnS) flakes have been produced via a modified atmospheric pressure vapor deposition method with SnS2 as the precursor. By coupling with silicon, an ultrabroadband photodetector has been achieved, exhibiting photoresponse across 365-2200 nm. The long-wave photosensitivity beyond the intrinsic limits of both Si and SnS has been associated with the interlayer transition, where electrons are excited from the valence band of SnS to the conduction band of Si. Under a self-powered working mode, the m-SnS/Si photodetector achieves the optimal on/off ratio exceeding 104, responsivity of 0.70 A W-1, and detectivity of 2.84 × 1010 Jones. In addition, by virtue of the intrinsic anisotropic crystal structure of SnS, the device manifests pronounced polarization-resolved photoresponse. To consolidate the practical applicability, panchromatic imaging, mixed liquid identification, optical communications, and intelligent agriculture applications have been achieved by exploiting the m-SnS/Si photodetector as a signal receiver. On the whole, this study depicts a new paradigm for the realization of advanced multifunctional optoelectronic systems.