Novel procedure to prepare cadmium stannate films using spray pyrolysis technique for solar cell applications

Abstract

Thin films of cadmium stannate was prepared using low cost cadmium acetate and tin (II) chloride precursors by spray pyrolysis technique at three different substrate temperatures of 400, 450 and 5000 C. A novel procedure of simultaneously forming additional layer, introduced for the first time in this work, on the already coated cadmium stannate film reduced the sheet resistance from 160 ohms/sq to 15 ohms/sq. Further, it is identified that the formation of additional layer does not affect the structural and optical properties of the cadmium stannate films, but improves the electrical property; thus the formation of additional layer seems to be an effective alternate for annealing the films at high temperature in the presence of Ar, CdS, Ar/CdS mixture, hydrogen or nitrogen to improve the structural, electrical and optical properties of the cadmium stannate films as has been reported in the literature. The maximum optical transmittance value of the prepared cadmium stannate film is about 99.8 % and the optical band gap energy value is about 2.9 eV.