Characterization of interface between CuInSe2 and In2O3

CuInSe2/In2O3 structures were formed by depositing CuInSe2 films by stepwise flash evaporation onto In2O3 films, which were grown by DC reactive sputtering of In target in presence of (Ar+O2) gas mixture. Phase purity of the CuInSe2 and In2O3 films was confirmed by Transmission Electron Microscopy (TEM) studies. X-ray diffraction (XRD) results on CuInSe2/In2O3/glass structures showed sharp peaks corresponding to (112) plane of CuInSe2 and (222) plane of In2O3. Rutherford Backscattering Spectrometry (RBS) investigations were carried out on CuInSe2/In2O3/Si structures in order to characterize the interface between In2O3 and CuInSe2. The results show that the CuInSe2 films were near stoichoimetric and In2O3 films had oxygen deficient composition. CuInSe2/In2O3 interface was found to include a ∼20 nm thick region consisting of copper, indium and oxygen. Also, the In2O3/Si interface showed the formation of ∼20 nm thick region consisting of silicon, indium and oxygen. The results are explained on the basis of diffusion/reaction taking place at the respective interfaces.