LAUSR

Abstract Coral reefs, nano-particles forming cage and a snail like nano-crystalline CuIn x S 1 − x ( x  = 0.1, 0.2, 0.3, 0.4 and 0.5) thin films having (1 1 2) oriented tetragonal CuInS 2 phase are fabricated on glass substrate at substrate temperature 380 °C using spray pyrolysis technique. The effect of In doping on the structural, morphological, optical and transport properties of these films have been studied in details. Optical study reveals that all samples are direct band gap semiconductor having high absorption coefficient (∼10 5 ). The band gap varies from 1.43 eV to 1.66 eV with increase of In doping. The electrical resistivity decreases with the increase of doping and temperature indicates the semiconducting nature of these films. The carrier concentration of all samples are found ∼10 14  cm −3 and the samples are p-type semiconductor for doping concentrations up to x  = 0.4 whereas, they become n-type for x  = 0.5 and more confirmed by both Hall voltage and thermo power measurement.