Zero-point band gap renormalization in semiconductors for optoelectronic applications

Details

Supervisors

Gonze, Xavier

Faculty

Ecole polytechnique de Louvain

Degree label

Master [120] : ingénieur civil physicien, à finalité spécialisée

Abstract

This work investigates the zero-point renormalization (ZPR) and temperature dependence of the band gap in 10 semiconductors, focusing on zero-point lattice expansion (ZPLE) and electron-phonon interaction (EPI). Within the DFT formalism, the electron-phonon interaction was simulated by the AHC theory implemented in the ABINIT software, resulting in an uncertainty of less than 10 % in most of the cases. The zero-point lattice expansion was studied using the quasiharmonic (QHA) approximation, revealing band gap contributions between 6 and 68 meV for most materials, except for GaSe and InSe, where strong anisotropy caused the QHA to fail. The temperature dependence was also investigated for few semiconductors, comparing simulation results with experimental data.