Temperature Dependence of Silicon Luminescence Due to Splitting of the Indirect Ground State

Abstract

The temperature dependence of the ratio of LO- to To-phonon-assisted recombination luminescence of the indirect exciton in silicon is reported. The ratio is found to differ from that observed in absorption and to vary from ∼ 0.3 at 2°K to ∼ 0.1 at 13°K. The variation of the ratio with temperature is shown to be due to the splitting of the ground state of the exciton by several tenths of a meV. The relevance of these results to the recombination from the electron-hole condensate in silicon is discussed.