Preparation and characterization of CuInxAl1-xS2 films using the sulfurization of metal precursors for photoelectrochemical applications

In this study, CuIn(x)A(1-x)S(2) multi-componentsemiconductor films are deposited onto glass substrates and indium-doped tin oxide-coated glass substrates using the sulfurization of thermally evaporated Cu-In-Al metal precursors. X-ray diffraction and energy-dispersive analysis of X-ray results show that the crystal phase of the samples is the tetragonal CuInS2 phase. With an increase in Al content in the metal precursors, the peaks in the XRD patterns of samples shift to higher angles. The thickness and direct band gap of the films are in the ranges of 1.77-1.86 mu m and 1.39-1.42 eV, respectively. All samples are p-type semiconductors with the carrier concentration and mobility in the ranges of 8.3 x 1016 to 1.1 x 10(14) cm(-3) and 14.4-45.4 cm(2)/(V s), respectively. The Mott-Schottky measurements of samples show the flat-band potentials of samples to be -0.65 to -0.08 V vs. an Ag/AgCl electrode in 0.5 M K2SO4 aqueous solution. The maximum cathodic enhancement current density of the samples on indiumdoped tin oxide-coated glass substrates with an Al/(In+ Al) molar ratio of 0.12 in the samples is 0.6 mA/ cm(2) at an external potential of -1.0 V (vs. Ag/AgCI electrode) in 0.5 M K2SO4 aqueous solution under illumination. The results show that high-quality CuInxAl1-xS2 films can be obtained using the sulfurization of Cu-In-Al metal precursors for photoelectrochemical applications. Crown Copyright (C) 2012 Taiwan Institute of Chemical Engineers. Published by Elsevier B.V. All rights reserved.