Van der Waals Heterostructure Mid-Infrared Emitters with Electrically Controllable Polarization States and Spectral Characteristics

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, in which tuning the polarity of the applied bias can switch their emission peak wavelengths and linear polarization states along two orthogonal orientations. 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, the time-averaged EL exhibits the characteristics of broad spectral coverage, encompassing the entire first mid-IR atmospheric window (λ: 3–5 μm), and electrically tunable spectral shapes.

Application and prospect of 2D materials in photodetectors

“…A two-ended mid-infrared transmitter is reported by Chen et al in which the peak wavelength and linear polarization state of the emission can be switched along two orthogonal directions by adjusting the polarity of the applied bias (figure 6(g)). By controlling the crystallographic orientations and engineering the band profile of heterostructures, the emissions of two junctions exhibit distinct spectral ranges and polarization directions (figure 6(h)) [131].…”

Black Phosphorus for Photonic Integrated Circuits

“…Overall, scientists proposed various light emitters based on BP with different structures, and their key parameters are summarized in Table 3 [ 114 – 120 ]. In addition to the in-plane anisotropy and thickness dependency, the temperature dependency and strain dependency of BP are the key factors affecting performance of the light emitters.…”

Mid-Infrared Light-Emitting Diodes Based on Black Phosphorus with Asymmetric Electrodes

“…In addition, electron–hole pairs (or excitons for thin layers) in BP have a low Auger recombination coefficient, offering the prospect for application in infrared optoelectronics. The reported BP-based mid-infrared LEDs are mainly typical p–n junctions such as BP/MoS 2 heterostructure. − Thin-layer MoS 2 is used as the n-region of electron conduction and BP is used as the p-region of hole conduction at positive bias . These types of p–n junction devices face the challenges of scalability, and the carrier injection scenario is sensitive to the thicknesses of the chosen flakes.…”