Electron-phonon interaction effects on the direct gap transitions of nanoscale Si films

摘要

This study shows that the dielectric function of crystalline Si quantum wells(c-Si QW) is influenced by both carrier confinement and electron-phononinteractions. The energy shifts and lifetime broadening of the excitonic E1direct gap transition of c-Si QWs from 2 to 10 nm are found to have asignificant dimensional and temperature dependence that can be traced tochanges in the phonon dispersion of nanoscale films. The influence ofelectron-phonon interactions on the dielectric function was verified byaltering the phonon dispersion using different dielectric layers above a 5 nmc-Si QW.