Diffusions in (In,Se)-Cu(In,Ga)Se-2/SnO2 thin film structures

In this article we study (In,Se)-Cu(In,Ga)Se-2/SnO2 thin film heterostructu res for solar cells, the light coming through SnO2. The Cu(In,Ga)Se-2 layer s were grown by close-spaced vapor transport and the (In,Se) layers by clos e-spaced sublimation. We first clear up the main results obtained in the fa brication and characterization of the samples. Then, the diffusion mechanis ms appearing in these structures are studied, from secondary ion mass spect roscopy studies. Copper diffusion is probably the key of the creation of a p-n junction lying near SnO2 and responsible for the photovoltaic effect th at is observed. (C) 2000 American Institute of Physics. [S0021-8979(00)0312 3-6].