ILGAR technology IV:: ILGAR thin film technology extended to metal oxides

An ion layer gas reaction (ILGAR) technique for the deposition of thin metal oxide films such as zinc oxide has been developed. In a cyclic process a solid precursor layer was applied on a substrate by dipping in a Zn(ClO4)2 solution and subsequent drying. Reaction with gaseous NH3/H2O led to a hydroxide layer which is thermally dehydrated to ZnO. The steps were repeated until the desired layer thickness was obtained. Under optimized conditions the chlorine remainder lay below 0.3 at%. X-ray-diffraction revealed a preferred orientation concerning the (0 0 2) plane. The band gap was determined to Egap=3.38 eV. First ZnO/CIGSSe solar cells showed efficiencies of 10.7%.