Scattering of Hot Excitons in Quantum Wells

TL;DR

This paper calculates the scattering probabilities of hot excitons in narrow quantum wells, considering exciton-phonon interactions and mode contributions, providing insights into exciton relaxation and scattering processes.

Contribution

It introduces a detailed calculation of exciton-phonon scattering in narrow quantum wells using an envelope function Hamiltonian approach, highlighting the role of confined and interface modes.

Findings

Confined and interface modes significantly influence exciton scattering rates.

Even parity electrostatic potential states dominate excitonic scattering.

Results have implications for multiphonon resonance Raman scattering in narrow QWs.

Abstract

The scattering probabilities of hot excitons in narrow quantum wells (QWs)are obtained. The exciton-phonon matrix element is considered by using an envelope function Hamiltonian approach in the strong quantization limit where the QW width is smaller than the exciton bulk Bohr radius. The Fr\"{o}hlich-like interaction is taken into account and the contribution of the confined and interface modes to the scattering probability are calculated as a function of quantum well width, electron and hole effective masses, and in-plane center-of-mass kinetic energy. Inter- and intra-subband excitonic transitions are discussed in term of the phonon scalar potential selectionrules. It is shown that even parity electrostatic potential states for confined and interface modes give the main contribution to the excitonic scattering rate. The consequences of exciton relaxation and scattering probability present for the multiphonon resonance Raman scattering in narrow QWs are briefly discussed.