Electrochemical Deposition of n-Type ZnSe Thin Film Buffer Layer for Solar Cells

Zinc selenide thin films on ITO glass substrate have been grown by an electrochemical deposition technique at a low temperature of 50 degrees C. The bath solution was maintained at three different pH values and the effect of pH on the nature of the deposited films studied. Profilometer studies showed the roughness of ZnSe thin films obtained from the bath in which SeO2 was the Se source is lower than that of the films obtained from the bath in which SeCl4 was the Se source. The atomic percentage ratio for zinc and selenium of the ZnSe thin films obtained from the bath in which SeO2 was the Se source was found to be 49.7:50.3. GAXRD studies confirmed that the as-deposited ZnSe thin films belong to the cubic system with (111) plane as the dominant peak. When SeCl4 was used as Se source the thin films showed peaks due to the cubic system along with hexagonal (100) reflection indicating a mixed phase. The absorption coefficient's fall is sharper for the films obtained from the bath in which SeO2 was the Se source than those films obtained from the bath in which SeCl4 was the Se source due to the presence of hexagonal phase. (C) 2014 The Electrochemical Society. All rights reserved.