Multi Fermi level pinning at metal/Cu(InGa)(SeS)(2) interfaces

Metal contacts to chemically etched Cu(InGa)(SeS)(2) layers have been investigated using current-voltage and capacitance-voltage techniques. Oxidising chemicals enhance the Fermi level pinning at metal/Cu(InGa)(SeS)2 interfaces. The formation of a Schottky barrier at metal/p-Cu(InGa)(SeS)2 interface is dominated by Fermi level pinning at one of the four levels, 0.77 +/- 0.02, 0.84 +/- 0.02, 0.93 +/- 0.02 and 1.03 +/- 0.02 eV above the valence band maximum. These observed levels determined from current-voltage measurements show a good agreement with some of the previously published photoluminescence, deep level transient spectroscopy and photo acoustic spectroscopy observations. The capacitance-voltage measurements showed that this material has near ideal doping concentration of 1.0 X 10(16) cm(-3) for fabricating solar cell devices. (c) 2008 Elsevier BY. All rights reserved.