Very efficient light emission from bulk crystalline silicon

Abstract

Due to its indirect bandstructure, bulk crystalline silicon is generally regarded as a poor light emitter. In contrast to this common perception, we report here on surprisingly large external photoluminescence quantum efficiencies of textured bulk crystalline silicon wafers of up to 10.2% at T=130 K and of 6.1% at room temperature. Using a theoretical model to calculate the escape probability for internally generated photons, we can conclude from these experimental figures that the radiative recombination probability or internal luminescence quantum efficiency exceeds 20% at room temperature.