Direct Observation of Layer-Dependent Electronic Structure in Phosphorene

TL;DR

This study experimentally reveals how the electronic properties of few-layer phosphorene change with layer number, showing its potential for electronic and photonic applications due to its layer-dependent bandgap and high mobility.

Contribution

The paper provides the first experimental observation of layer-dependent electronic structure in phosphorene, confirming theoretical predictions and highlighting its optoelectronic advantages.

Findings

Electronic structure varies significantly with layer number.

Strong photoluminescence indicates direct bandgap in few-layer phosphorene.

Interband optical transitions cover visible to mid-infrared spectrum.

Abstract

Phosphorene, a single atomic layer of black phosphorus, has recently emerged as a new twodimensional (2D) material that holds promise for electronic and photonic technology. Here we experimentally demonstrate that the electronic structure of few-layer phosphorene varies significantly with the number of layers, in good agreement with theoretical predictions. The interband optical transitions cover a wide, technologically important spectrum range from visible to mid-infrared. In addition, we observe strong photoluminescence in few-layer phosphorene at energies that match well with the absorption edge, indicating they are direct bandgap semiconductors. The strongly layer-dependent electronic structure of phosphorene, in combination with its high electrical mobility, gives it distinct advantages over other twodimensional materials in electronic and opto-electronic applications.