Dynamical Evolution of Anisotropic Response in Black Phosphorus under Ultrafast Photoexcitation

TL;DR

This study investigates how ultrafast photoexcitation affects the anisotropic electronic properties of black phosphorus, revealing enhanced anisotropy in transient reflectivity and conductivity, which could enable advanced high-field electronic and optoelectronic devices.

Contribution

The paper provides the first detailed analysis of the dynamical evolution of anisotropic electronic properties in black phosphorus under ultrafast photoexcitation using angle-resolved transient reflection spectroscopy.

Findings

Enhanced anisotropy of reflectivity in the quasi-equilibrium state

Significant increase in anisotropic dynamical conductivity in hot carrier regime

Potential for developing angle-sensitive electronic and optoelectronic devices

Abstract

Black phosphorus has recently emerged as a promising material for high performance electronic and optoelectronic device for its high mobility, tunable mid-infrared bandgap and anisotropic electronic properties. Dynamical evolution of photo excited carriers and its induced change of transient electronic properties are critical for materials' high field performance, but remains to be explored for black phosphorus. In this work, we perform angle resolved transient reflection spectroscopy to study the dynamical evolution of anisotropic properties of black phosphorus under photo excitation. We find that the anisotropy of reflectivity is enhanced in the pump induced quasi-equilibrium state, suggesting an extraordinary enhancement of the anisotropy in dynamical conductivity in hot carrier dominated regime. These results raise enormous possibilities of creating high field, angle sensitive electronic, optoelectronic and remote sensing devices exploiting the dynamical electronic anisotropic with black phosphorus.