The investigation of spray pyrolysis grown CdS thin films doped with flourine atoms

Undoped and F-doped CdS thin films were succesfully grown on the glass substrates by the spray prolysis method. X-ray diffraction results showed that all the samples had hexagonal wurtzite structure with the (1 0 1) preferred orientation. It was found from scanning electron microscopy that an increase in the grain size was observed after F-doping. The band gap value of CdS thin films increased from 2.38 eV to 2.42 eV with the increase of F concentration from 0 to 6 at.%. The intensity of room temperature photoluminescence spectrum of undoped CdS thin films enhanced with the increment of F-doping amount that is related to the increase of point defects formed by the flourine atoms. Electrical measurements showed that the carrier concentration increased from 1.93 x 10(12) cm(-3) to 7.62 x 10(12) cm(-3) when CdS thin films were doped with 2 at.% F. However, further increase in F amount up to 6 at.% caused a decrease in the carrier concentration. On the other hand, resistivity value first decreased from 1.26 x 10(5) SZ cm to 8.54 x 10(4) SZ cm with the increase of F-doping up to 2 at.% and then increased to 1.65 x 10(5) SZ cm for 6 at.% F-doping. It can be concluded that 2 at.% F-doped CdS thin films exhibited the best electrical and optical properties, which is suitable for the application of thin film solar cells. (C) 2015 Elsevier B.V. All rights reserved.