Depth profiling study of in situ CdCl2 treated CdTe/CdS heterostructure with glancing angle incidence X-ray diffraction

CdTe thin films have been deposited using spray pyrolysis technique without and with in situ CdCl₂ treatment. Scanning electron microscopy studies show enhanced grain growth in the presence of CdCl₂. Glancing angle incidence X-ray diffraction is used for the micro structural study of polycrystalline CdS/CdTe heterostructure at different depths by changing the incident angle. Spraying of CdCl₂ on CdS prior to CdTe deposition promotes S diffusion throughout CdTe film and also Te diffusion into CdS. Whereas spraying of CdCl₂ in between CdTe deposition prevents S diffusion partially and Te diffusion completely. There is an associated change in the microstress of the CdTe film at different layers. The films without CdCl₂ treatment show compressive microstress varying from −98 to −158 MPa with increasing incident angle. CdCl₂ spray during CdTe deposition shows compressive microstress, which varies from −98 MPa at the interface to −19 MPa near the surface and CdCl₂ spray prior to CdTe deposition leads to a mildly tensile stress, from +40 to +20 MPa, which is very close to the standard shear stress of 10 MPa for CdTe.