Highly sensitive detection of polarized light using a new IV-V group 2D orthorhombic SiP

Chunlong Li, ^a Shanpeng Wang, ^*,a,b, Chenning Li, ^a Tongtong Yu, ^a Ning Jia, ^a Jie Qiao, ^a Min Zhu, ^a Duo Liu, ^a,b and Xutang Tao ^*,a,b

Abstract

IV-V group 2D semiconductors, such as GeP and GeAs, have attracted increasing attentions and tend to be a new research hotspot due to high in-plane anisotropic properties. As one among them, orthorhombic SiP (o-SiP) deserves more attention due to high enough carrier mobility, large band gap, excellent stability and even direct band gap in monolayer.  In this work, the experimental Raman modes were identified based on DFT calculations and then we demonstrate highly in-plane anisotropy of phonon vibrations by angle-resolved polarized Raman spectroscopy. In addition, o-SiP based photodetectors were fabricated to investigate in-plane anisotropic photoresponse. The results indicate that o-SiP is an alternative photodetector with high responsivity and well-reproducible cycles. Furthermore, high anisotropy was revealed with a notably anisotropic on/off switching ratio. Our results present that o-SiP is a new member of IV-V group 2D semiconductors with intriguing optoelectronic properties, and will open new opportunities for promising applications in advanced photonic and optoelectronic devices.