Abstract
M.Sc.
Current solar cell research programmes in general aim to develop a high conversion efficiency photovoltaic (PV) module from high quality thin films. In this study, Cu (In,Ga)Se2 (CIGS) thin films were grown and characterized. These films were grown by selenization of Cu-In-Ga precursors. These precursors were prepared by co-sputtering In and (Cu, Ga). All the precursors were grown on Mo coated soda lime glass substrates. The selenization was conducted under different conditions in Ar/H2Se atmosphere, i.e. taking different values of flow rate of H2Se (5.00, 1.00, 0.25 mol%) in Ar, temperature (350, 450, 550 ºC) and time (10, 20, 30, 40, 50, 60 min). At each selenization condition, two samples were placed at different positions in the chamber. The structural properties of the produced films were analyzed by the techniques of X-ray Diffraction (XRD) for phases, Scanning Electron Microscopy (SEM) for morphology and Energy Dispersive Spectroscopy (EDS) for the bulk composition. The effect of temperature variation, the effect of flow rate variation and the effect of time variation were analyzed by comparing the structural properties as analyzed by the techniques mentioned. All in all this specific study delivers important information about the sensitivity of Cu(In,Ga)Se2 (CIGS) thin films to the temperature, gas flow rate and exposure time of the selenization step.
Doctor C.A. Engelbrecht
Professor Vivian Alberts