Quantitative growth of thin Cu2S layers in chemiplated thin film CdS:Cu2S solar cells was observed by studying the depth profile concentrations of copper and sulphur by using the X-ray photo-electron spectroscopy technique. From a study of the spatial distributions of Cd, Cu and S, it was deduced that, in deep layers, the Cu originated from grain boundaries. In the chemiplating process, the copper diffusion was 500 times faster in the grain boundary than in mid-grain. Short heat treatment of the cells caused redistribution of Cd and Cu in the junction, making the interface sharper. Analysis yielded,

D(cm2/s) = 5.8 x 10-11 exp[-0.229(eV)/kT]

for the mid-grain and,

D(cm2/s) = 1.06 exp[-0.964(eV)/kT]

for the grain boundary.

A.C.Rastogi, S.Salkalachen: Solar Cells, 1983, 9[3], 185-202