Preparation of CuInSe₂ thin films by a chemical solution method

A low cost chemical solution method for the preparation of CuInSe₂ thin films was proposed. The changes of film properties were studied, which were caused by several parameters of the experiments, including the annealing temperature of the precursor films, the annealing temperature for selenization and different substrates. Copper nitrate and indium chloride were used to prepare the precursor solution. The precursor films were processed by the spin-coating method from the solution, and then selenized at 480°C to obtain CIS thin films. XRD results show chalcopyrite structure with high crystallinity. SEM images show large grains and relatively smooth and dense surface. EDX analysis results indicate that the ratios of components were in a reasonable range, slightly poor in copper and rich in selenium. The sample films were sandwiched into CIS prototype solar cells as the absorbing layer. The photovoltaic response of a single CIS layered cell reaches 1.6%.