Van der Waals heterostructure mid-infrared emitters with electrically controllable polarization states and spectral characteristics

TL;DR

This paper introduces electrically controllable mid-infrared light emitters using layered black phosphorus and related materials, enabling independent spectral and polarization tuning without complex optics.

Contribution

The work demonstrates a novel two-terminal heterostructure emitter with independently controllable spectral and polarization properties in the mid-IR range.

Findings

Emitters exhibit distinct spectral ranges and polarization directions.

Electroluminescence can be independently activated by bias polarity.

Broad spectral coverage across the first mid-IR atmospheric window.

Abstract

Modern infrared (IR) microscopy, communication, and sensing systems demand control of the spectral characteristics and polarization states of light. Typically, these systems require the cascading of multiple filters, polarization optics and rotating components to manipulate light, inevitably increasing their sizes and complexities. Here, we report two-terminal mid-infrared (mid-IR) emitters with electrically controllable spectral and polarization properties. Our devices are composed of two back-to-back p-n junctions formed by stacking anisotropic light-emitting materials, black phosphorus and black arsenic-phosphorus with MoS2. By controlling the crystallographic orientations and engineering the band profile of heterostructures, the emissions of two junctions exhibit distinct spectral ranges and polarization directions; more importantly, these two electroluminescence (EL) units can be independently activated, depending on the polarity of the applied bias. Furthermore, we show that when operating our emitter under the polarity-switched pulse mode, its EL exhibits the characteristics of broad spectral coverage, encompassing the entire first mid-IR atmospheric window, and electrically tunable spectral shapes. Our results provide the basis for developing groundbreaking technology in the field of light emitters.