An approach to alternative post-deposition treatment in CdTe thin films for solar cell application

Abstract

Abstract In this study, preliminary investigation of different post-deposition treatments using materials such as cadmium chloride (CdCl2), magnesium chloride (MgCl2), copper chloride (CuCl2), and silver nitrate (AgNO3) has been reported for close-spaced sublimation (CSS) grown cadmium telluride (CdTe) thin films. The treatment of CdTe thin films was conducted in open air at 390 °C. Treated CdTe thin films were then exposed to different characterization tools to explore the effects of treatment on the structural and optoelectronic properties of CdTe films. Hall effect measurement was executed for electrical properties measurement as well as X-ray diffraction (XRD) analysis was utilized for the detection of structural parameters. The energy band gap was obtained at approximately 1.47 eV for all the treated films. CuCl2 treated CdTe films exhibited a higher carrier concentration of 1015 cm−3 than other treatments. The impact of Cu diffusion during CuCl2 treatment was suggested as an effect of doping during recrystallization. The average grain sizes changed moderately in the range 4–7 μm for different post-deposition treatments. The optimized results can provide an indication for other materials to be used as the alternative post-deposition treatment to conventional CdCl2.