CdS1−yTey thin films: Production and bandgap investigation

► CdS1−yTey thin films were produced. ► CdS1−xTex is always formed in the CdS/CdTe interface in SnO2/CdS/CdTe solar cells. ► SEM images, EDAX and transmittance measurements were used to characterize the films. ► The second derivative of the absorbance was used to obtain the bandgap energy.