The effect of sodium doping to CuInSe_2 monogram powder properties

摘要

The effect of sodium doping to the electrical and photoluminescence properties of CuInSe_2 monograin powders was studied. Sodium was added in controlled amounts from 5 x 10~(16) cm~(-3) to 1 x 10~(20) cm~(-3). The photoluminescence spectra of Na-doped stoichiometric CuInSe_2 powders had two bands with peak positions at 0.97 and 0.99 eV. The photoluminescence bands showed the shift of peak positions depending on the Na doping level. Peak positions with maximum energy were observed if added sodium concentration was 1 x 10~(19) cm~(-3). This material had the highest carrier concentration 2 x 10~(17) cm~(-3). In the case of stoichiometric CuInSe_2 (Cu:In:Se = 25.7:25.3:49.0), Na doping at concentrations of 3 x 10~(17) cm~(-3) and higher avoided the precipitation of Cu-Se phase. Solar cells output parameters were dependent on the Na doping level. Sodium concentration 3 x 10~(18) cm~(-3) resulted in the best open-circuit voltage.