CuIn(SxSe1-x)2 films prepared by graphite box annealing of In/Cu stacked elemental layers

CuIn(SxSe1-x)(2) films were synthesized by sulphurization of In/Cu stacked elemental layers deposited onto glass and Mo-coated glass substrates followed by selenization by graphite box annealing. The films, thus synthesized, were characterized by measuring electrical, optical and microstructural properties. The microstructure and hence the physical properties of the films depended critically on the amount of sulphur incorporation. Nature of charge carriers depended on Cu/In, (S + Se)/(Cu + In) and S/(S + Se) ratios while their concentrations varied between 10(16) and 10(19) cm(-3). Grain boundary scattering effects were critically studied by measuring the electrical conductivity (sigma) and Hall mobility (mu) simultaneously on the same sample. Optical transmittance studies indicated the band gap to vary within 0.98-1.40eV with x values. The photoluminescence spectra, recorded at 80 K were dominated by the excitonic peak located within 1.40-1.6eV followed by a small peak within similar to 0.96-0.98 eV arising due to transition from conduction band to neutral acceptor (V-Cu) or exciton bound to ionized acceptor (Cu-In) states. (C) 2001 Elsevier Science Ltd. All rights reserved.