Excitonic Terahertz Emission from Silicon at Steady-State Interband Photoexcitation

We report results of experimental study of terahertz photoluminescence from silicon arising due to intra-exciton radiative transitions. These transitions are excited during the binding of nonequilibrium electrons and holes into free excitons. Experiments are carried out on high-purity Si crystals with a resistivity of 12 kOhm·cm at helium temperatures and under interband photoexcitation with densities from 0.1 to 140 W/cm².