Extraordinary Photoluminescence and Strong Temperature/Angle-Dependent Raman Responses in Few-Layer Phosphorene

TL;DR

This study reveals that few-layer phosphorene exhibits strong, layer-dependent photoluminescence and temperature-sensitive Raman responses, enabling optical identification of crystal orientation and providing insights into its band structure.

Contribution

The paper provides experimental evidence of layer-dependent photoluminescence and anisotropic Raman responses in few-layer phosphorene, confirming theoretical predictions and introducing a rapid optical orientation method.

Findings

Strong layer-dependent photoluminescence observed

Temperature-sensitive Raman scattering in phosphorene

Optical method developed for crystal orientation detection

Abstract

Phosphorene is a new family member of two-dimensional materials. We observed strong and highly layer-dependent photoluminescence in few-layer phosphorene (2 to 5 layers). The results confirmed the theoretical prediction that few-layer phosphorene has a direct and layer-sensitive band gap. We also demonstrated that few-layer phosphorene is more sensitive to temperature modulation than graphene and MoS2 in Raman scattering. The anisotropic Raman response in few-layer phosphorene has enabled us to use an optical method to quickly determine the crystalline orientation without tunneling electron microscope (TEM) or scanning tunneling microscope (STM). Our results provide much needed experimental information about the band structures and exciton nature in few-layer phosphorene.