Influence of substrate temperature on structural, electrical and optical properties of flash evaporated CuIn0.60Al0.40Se2 thin films

CuIn0.60Al0.40Se2 thin films were grown by the flash evaporation method onto glass substrates held at temperatures in the range 303–623 K. The influence of substrate temperature on growth of the films was studied. The growth of the highly (111) oriented CuIn0.60Al0.40Se2 thin films was observed at TS = 598 K exhibiting sphalerite structure. The surface morphology of CuIn0.60Al0.40Se2 films deposited at TS = 623 K indicates segregation of Cu2–xSe binary phase. The electrical resistivity was around 66 Ω cm (300 nm) with p-type conductivity for the films deposited at 598 K. The temperature dependence of the electrical conductivity suggested that above 493 K the conduction mechanism was intrinsic, whereas extrinsic/impurity conduction dominated in the range 303–473 K. The single phase CuIn0.60Al0.40Se2 films showed an optical bandgap of 1.37 eV. (© 2009 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)