Study of the band – gap shift in CdS films : Influence of thermal annealing in different atmospheres

Study of the band–gap shift in CdS films: Influence of thermal annealing in different atmospheres. Abstract We study by photoacoustic spectroscopy the band–gap shift effect of CdS films. The CdS films were grown by chemical bath deposi-tion and exposed to different annealing atmospheres over a range of temperature in which the sample structure is observed to change. We show the band–gap evolution as a function of temperature of thermal annealing and determine the process which produces the best combination of high band–gap energy and low resistivity. It allows us to know a possible procedure to obtain low–resistivity CdS/CdTe solar cells with high–quantum efficiency.