Cu In,Ga S2 films prepared by two stage evaporation on ZnO coated substrates

Abstract

We have prepared Cu In,Ga S2 films with an almost homogeneous Ga depth distribution using the two stage sequential multi source evaporation process on soda lime glass SLG substrates with one of three different kinds of back contact Mo 1000nm , ZnO 500nm , and Mo 30nm ZnO 500nm , respectively. We have investigated the depth profiles of Zn and Na diffused from SLG in Cu In,Ga S2 films by secondary ion mass spectroscopy SIMS and compare them to those in films prepared by co evaporation . The efficiencies are higher on Mo ZnO than they are on ZnO. It was observed by SIMS that the amount of Zn in Cu In,Ga S2 on Mo ZnO is lower than it is in Cu In,Ga S2 on ZnO. The obtained efficiencies are generally higher with two stage evaporation than with co evaporation. The Na concentration in Cu In,Ga S2 prepared by two stage evaporation is two orders of magnitude higher than in co evaporated films