Electrodeposited CdS on CIS pn junctions

We have been investigating the electrochemical deposition of thin films and junctions of cadmium sulfide (CdS) and copper indium diselenide (CIS). We show that it is possible to fabricate pn junctions based on n-type CdS and p-type CIS entirely by electrodeposition. CIS is considered to be one of th e best absorber materials for use in polycrystalline thin-film photovoltaic solar cells. CdS provides a closely lattice-matched window layer for CIS. Electrodeposition is a simple and inexpensive method for producing thin-fil m CdS and CIS. We have produced both p- and n-type CIS thin films, as well as a CdS on CIS pn junction via electrodeposition. Elemental analysis of th e CdS and CIS thin films was performed using X-ray photoelectron spectrosco py and energy dispersive spectroscopy. Optical band gaps were determined fo r these films using optical transmission spectroscopy. Carrier densities of the CIS films as a function of their deposition voltage were determined fr om capacitance vs. voltage measurements using Al Schottky barriers. Current vs. voltage characteristics were measured for the Al on CIS Schottky barri ers and for the CdS on CIS pn junction. (C) 1999 Elsevier Science B.V. All rights reserved.