Field Effect Optoelectronic Modulation of Quantum-Confined Carriers in Black Phosphorus

TL;DR

This study investigates how electric fields modulate the infrared optical properties of thin black phosphorus, revealing effects like band-filling and quantum confinement, with potential applications in mid-infrared optoelectronic devices.

Contribution

It provides experimental evidence of field-induced spectral changes in black phosphorus, including the Burstein-Moss shift and Franz-Keldysh effect, advancing understanding of its optoelectronic modulation capabilities.

Findings

Spectral changes consistent with BM shift and QCFK effect observed

Transmission extinction modulation over 2% achieved

Optoelectronic modulation potential demonstrated for mid-infrared applications

Abstract

We report measurements of the infrared optical response of thin black phosphorus under field-effect modulation. We interpret the observed spectral changes as a combination of an ambipolar Burstein-Moss (BM) shift of the absorption edge due to band-filling under gate control, and a quantum confined Franz-Keldysh (QCFK) effect, phenomena which have been proposed theoretically to occur for black phosphorus under an applied electric field. Distinct optical responses are observed depending on the flake thickness and starting carrier concentration. Transmission extinction modulation amplitudes of more than two percent are observed, suggesting the potential for use of black phosphorus as an active material in mid-infrared optoelectronic modulator applications.