  Physical vapor high-temperature deposition of CdTe thin films is one of the
main methods for preparing high-efficiency CdTe solar cells, but
high-temperature deposition also has an impact on the internal structure of the
film. The difference in thermal expansion coefficients between the substrate
and CdTe leads to the generation of internal stress in the CdTe thin film
during the cooling process. In this work, we prepared thin films with different
substrate temperatures using a homemade GVD device, and observed by SEM that
the crystallization quality of the film gradually improved with the increase of
substrate temperature, but accompanied by the shift of XRD peak position. We
calculated the internal stress situation of the film by the shift amount, and
the possible causes of stress generation were speculated by the results of TEM
and SAED to be the combined effects of the different thermal expansion
coefficients between the substrate and the film and the stacking fault defects
inside the film.
