PREPARATION AND CHARACTERIZATION OF MN DOPED SPRAYED P-CUINS2 FILMS

CuInS2, a promising material for tandem solar cell realisation, is doped with Mn, a probing dopant for crystal fields and a creator of fluorescent levels in several crystals. 0.7, 1.2 and 1.9 at % of Mn doped p-CuInS2 films were prepared by spray pyrolysis. XRD studies confirmed the chalcopyrite structure with c = 11.02 and a = 5.51 angstrom. The direct bandgap obtained from transmission spectra was found to increase with Mn content in the range 1.38-1.56 eV. Hall effect and conductivity studies in the temperature range 190-273 K showed a decrease of hole concentration with doping indicating the creation of donor levels by Mn. The observed rise in conductivity with temperature may be attributed to increase of hole mobility due to ionised impurity scattering.