Diffusions in (In,Se)-Cu(In,Ga)Se2/SnO2 thin film structures

In this article we study (In,Se)-Cu(In,Ga)Se-2/SnO2 thin film heterostructures for solar cells, the light coming through SnO2. The Cu(In,Ga)Se-2 layers were grown by close-spaced vapor transport and the (In,Se) layers by close-spaced sublimation. We first clear up the main results obtained in the fabrication and characterization of the samples. Then, the diffusion mechanisms appearing in these structures are studied, from secondary ion mass spectroscopy studies. Copper diffusion is probably the key of the creation of a p-n junction lying near SnO2 and responsible for the photovoltaic effect that is observed. (C) 2000 American Institute of Physics. [S0021-8979(00)03123-6].