Polarized Light-Emitting Diodes Based on Anisotropic Excitons in Few-Layer ReS<sub>2</sub>.

Wang, Junyong; Zhou, Yong Justin; Xiang, Du; Ng, Shiuan Jun; Watanabe, Kenji; Taniguchi, Takashi; Eda, Goki · Adv Mater · 2020

basic_science · Level V

Where this comes from

Abstract

An on-chip polarized light source is desirable in signal processing, optical communication, and display applications. Layered semiconductors with reduced in-plane symmetry have inherent anisotropic excitons that are attractive candidates as polarized dipole emitters. Herein, the demonstration of polarized light-emitting diode based on anisotropic excitons in few-layer ReS<sub>2</sub> , a 2D semiconductor with excitonic transition energy of 1.5-1.6 eV, is reported. The light-emitting device is based on minority carrier (hole) injection into n-type ReS<sub>2</sub> through a hexagonal boron nitride (hBN) tunnel barrier in a metal-insulator-semiconductor (MIS) van der Waals heterostack. Two distinct emission peaks from excitons are observed at near-infrared wavelength regime from few-layer ReS<sub>2</sub> . The emissions exhibit a degree of polarization of 80% reflecting the nearly 1D nature of excitons in ReS<sub>2</sub> .