Radiative recombination coefficient in crystalline silicon at low temperatures < 77 K by combined photoluminescence measurements

Spectral photoluminescence (sPL) and modulated photoluminescence (MPL) measurements were applied to determine the band-to-band radiative recombination coefficient, Brad, in crystalline silicon. We used precursors of n-type crystalline silicon solar cells consisting of two different wafers passivated with aluminum oxide stacks or intrinsic hydrogenated amorphous silicon, respectively. So far values for Brad can be found in the literature only above 77 K. In this high-temperature range the temperature dependence of Brad obtained using our combined sPL/MPL method is in good agreement with the available literature data for both samples. Interestingly, we have extended the measured range down to a temperature of 20 K and observed a strong increase of Brad by three orders of magnitude with decreasing temperature from 77 K to 20 K.