Effects of Annealing Pressure for Electrodeposited CuInSe₂ Solar Cell

Abstract

As-deposited CuInSe2 films by electrodeposition are generally amorphous. A better photoelectric conversion efficiency of solar cell device should be derived from crystallized CuInSe2 absorber layer, and also the schottky contact with the CdS layer. In this work, a high pressure atmosphere was applied during the heat treatment, which achieved level surface and better crystallization for CuInSe2 thin films. We optimized the atomic ratio of eletrodeposited CuInSe2 thin films, the parameters for annealing process and the fabrication of the entire device. Top view images from field-emission-scanning electron microscopy indicates well-defined grains of CuInSe2 films. Raman spectrum results of annealed CuInSe2 films show the presence of CuInSe2 phase, and no secondery phases such as Cu-Se were detected. Energy dispersive spectrometer analysis shows the composition atomic ratio of copper indium diselenide to be soichiometric. The measurement of solar simulater indicates an imrovement of conversion efficiency of CuInSe2 solar cell after employing the high pressure annealing process.