Further comments on the luminescence line shape of the free exciton in germanium

Abstract

The free-exciton luminescence line shape in germanium has been measured as a function of crystal temperature and free-exciton density. In order to fit these data, the theory includes nonparabolicity effects, collision broadening, and Gaussian broadening. From this fit, the bottom of the free-exciton band is at 712.8 \ifmmode\pm\else\textpm\fi{} 0.1 meV and the electron-hole droplet binding energy is 1.9 \ifmmode\pm\else\textpm\fi{} 0.2 meV.