Review of conductor-insulator-semiconductor (CIS) solar cells

Abstract The physics and technology of a new class of photovoltaic devices, namely the conductor-insulator-semiconductor (CIS) solar cells, are reviewed in this paper. The top layer in these diodes may be a transparent conducting metal film, an oxide or polymer semiconductor, an electrolyte or a combination of these, leading to a wide variety of metal-insulator-semiconductor (MIS), semiconductor-insulator-semiconductor (SIS) and electrolyte-insulator-semiconductor (EIS) structures. The thickness of the interfacial layer and the work function of the conductor are the important parameters in the optimization of these devices. By ensuring inversion at the interface of the base semiconductor, devices can be fabricated with properties which do not depend strongly on the surface states nor on other non-idealities of the interfacial layer. CIS solar cells with efficiencies comparable with the best p-n junction cells have been fabricated. Most of the presentation is related to single-crystal devices, and the non-crystalline (polycrystalline and amorphous) semiconductor devices are treated separately. Available stability and accelerated life test data indicate fairly stable operation of optimized devices. It is suggested that the research and development efforts have reached such a stage that a prototype production facility is viable.