Interface phenomena of organic semiconductor junctioned with metal and inorganic semiconductor

Abstract

We have studied on the junction characteristics of organic semiconductor-metal and organic semiconductor — inorganic semiconductor devices. Organic semiconductor was electro-polymerized on metal electrode by constant current method. Considering the formation of oxide layer at the interface in manufacturing process and high resistance of organic semiconductor, we can deduce them as a MIS structure. Usually, it was known that organic semiconductor have rectifying contact with low workfunction metal and ohmic contact with high workfunction metal. But by our experimental results, junction characteristics depend on metal oxide layer rather than workfunction of metals. This oxide layer largely depends on manufacturing process of devices. So we studied the effect of an electro-polymerization condition, film thickness, and doping density in junction characteristics. Also we investigated the solar energy conversion characteristics of these devices. Photon have to be reached near the depletion region to increase the conversion efficiency. We studied on the transparent inorganic semiconductor like CdS as a window material and interface phenomena.