Hydrogen concentration in chalcopyrite thin-film solar cells

A survey of the hydrogen concentration distribution in the various layers o f chalcopyrite solar cells is presented. Depth profiles were measured by th e nuclear reaction analysis method for the glass substrate, Mo back contact , Cu(In, Ga)S-2 or Cu(In, Ga)Se-2 absorber, CdS buffer, and ZnO window laye r. We find that hydrogen is present in all layers in concentrations exceedi ng the solubility of hydrogen in the corresponding crystalline bulk materia ls. This indicates that the deposition process and the polycrystallinity of the layers favor the uptake of hydrogen. The measured concentrations range from some 10(18) H/cm(3) in the absorber up to some 10(21) H/cm(3) in the CdS buffer layer. Effects of annealing at elevated temperatures are reporte d.