Defect-related light emission in the 1.4-1.7 μm range from Si layers at room temperature

High density of crystal defects is formed in Si layers during their growth on the nanostructured surface composed of dense arrays of Ge islands grown on oxidized Si substrates. Although these defect-rich Si layers exhibit intense photoluminescence only at low temperatures, the forward-biased diodes with the Si layers located in the region of the p-i-n(+) junction can emit light at room temperature. The difference suggests that the influence of thermal emission of carriers from defect states on the light emission intensity is essentially reduced when the spatial distribution of carrier density is governed by the bias voltage and band bending. The results show that Si layers emitting light in the 1.4-1.7 mu m range at room temperature can be prepared by means of growth.