Black Arsenic-Phosphorus: Layered Anisotropic Infrared Semiconductors with Highly Tunable Compositions and Properties

TL;DR

This paper introduces black arsenic-phosphorus (b-AsP), a new layered 2D semiconductor with highly tunable compositions and properties, capable of covering the long-wavelength infrared spectrum and exhibiting in-plane anisotropic optical characteristics.

Contribution

The study presents the discovery and characterization of b-AsP, a novel 2D layered semiconductor with tunable bandgaps and anisotropic optical properties, extending the electromagnetic spectrum coverage of 2D materials.

Findings

b-AsP has tunable bandgaps from 0.3 to 0.15 eV.

b-AsP exhibits in-plane anisotropic infrared absorption and Raman spectra.

b-AsP extends 2D materials' spectral range into the long-wavelength infrared regime.

Abstract

Two-dimensional (2D) layered materials with diverse properties have attracted significant interest in the past decade. The layered materials discovered so far have covered a wide, yet discontinuous electromagnetic spectral range from semimetallic graphene, insulating boron nitride, to semiconductors with bandgaps from middle infrared to visible light. Here, we introduce new layered semiconductors, black arsenic-phosphorus (b-AsP), with highly tunable chemical compositions and electronic and optical properties. Transport and infrared absorption studies demonstrate the semiconducting nature of b-AsP with tunable bandgaps, ranging from 0.3 to 0.15 eV. These bandgaps fall into long-wavelength infrared (LWIR) regime and cannot be readily reached by other layered materials. Moreover, polarization-resolved infrared absorption and Raman studies reveal in-plane anisotropic properties of b-AsP. This family of layered b-AsP materials extend the electromagnetic spectra covered by 2D layered materials to the LWIR regime, and may find unique applications for future all 2D layered material based devices.