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 ReS2 , 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 ReS2 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 ReS2 . The emissions exhibit a degree of polarization of 80% reflecting the nearly 1D nature of excitons in ReS2 .
Keywords: 2D semiconductors, anisotropic excitons; light-emitting diodes; linear polarization; rhenium disulfide (ReS2).
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