High-performance polarization-sensitive photodetectors on two-dimensional <i>β</i>-InSe

Abstract

Two-dimensional (2D) indium selenide (InSe) has been widely studied for application in transistors and photodetectors, which benefit from its excellent optoelectronic properties. Among the three specific polytypes (<i>γ</i>-, <i>ϵ</i>- and <i>β</i>-phase) of InSe, only the crystal lattice of InSe in <i>β</i>-phase (<i>β</i>-InSe) belongs to a non-symmetry point group of [Formula: see text], which indicates stronger anisotropic transport behavior and potential in the polarized photodetection of <i>β</i>-InSe-based optoelectronic devices. Therefore, we prepare the stable p-type 2D-layered <i>β</i>-InSe via temperature gradient method. The anisotropic Raman, transport and photoresponse properties of <i>β</i>-InSe have been experimentally and theoretically proven, showing that the <i>β</i>-InSe-based device has a ratio of 3.76 for the maximum to minimum dark current at two orthogonal orientations and a high photocurrent anisotropic ratio of 0.70 at 1 V bias voltage, respectively. The appealing anisotropic properties demonstrated in this work clearly identify <i>β</i>-InSe as a competitive candidate for filter-free polarization-sensitive photodetectors.