Work

Nonequilibrium phonon effects in midinfrared quantum cascade lasers

Year: 2014

Type: article

Abstract: We investigate the effects of nonequilibrium phonon dynamics on the operation of a GaAs-based midinfrared quantum cascade laser over a range of temperatures (77–300 K) via a coupled ensemble Monte Carlo simulation of electron and optical-phonon systems. Nonequilibrium phonon effects are shown to be important below 200 K. At low temperatures, nonequilibrium phonons enhance injection selectivity and efficiency by drastically increasing the rate of interstage electron scattering from the lowest injector state to the next-stage upper lasing level via optical-phonon absorption. As a result, the current density and modal gain at a given field are higher and the threshold current density lower and considerably closer to experiment than results obtained with thermal phonons. By amplifying phonon absorption, nonequilibrium phonons also hinder electron energy relaxation and lead to elevated electronic temperatures.

Source: Journal of Applied Physics

DOI: 10.1063/1.4896400

Authors: Y. B. Shi, I. Knezevic

Institution: University of Wisconsin–Madison

Language: English

Topic: Semiconductor Lasers and Optical Devices

Subfield: Electrical and Electronic Engineering

Field: Engineering

Domain: Physical Sciences

Open Access status: bronze

Funders: U.S. Department of Energy, Basic Energy Sciences, Division of Materials Sciences and Engineering

Awards: G1651959128, G2100470167, COUPLING ELECTRONS, PHONONS, AND PHOTONS: EFFICIENT MULTIPHYSICS SIMULATION OF NONEQUILIBRIUM QUANTUM TRANSPORT IN ELECTRICALLY AND OPTICALLY EXCITED