Effect of high-pressure annealing on the physical properties of CdTe thin films

Abstract

In the present work, the CdTe thin films were fabricated on the Ag substrate using thermal evaporation technique. The effect of post-deposition high-pressure annealing (PDHPA) of 0.2, 0.5 and 1 MPa at 500 °C on physical properties of CdTe thin films was studied. The structural, optical, and electrical properties of films were considered using grazing incidence X-ray diffraction, ultraviolet–visible spectrophotometer (UV–Vis), scanning electron microscopy, and transverse current–voltage (I–V) test. The structural analysis shows that both pristine and treated films have zinc blende crystal structure with strong preferred (220) orientation. The optical analysis revealed the enhancement of optical absorbance and decrement of the energy band gap of films with PDHPA. Moreover, our analysis indicates that the electrical conductivity of CdTe films increases with PDHPA. The SEM images show that the untreated films are uniform and homogeneous. Our results indicate that the cracking is observed in treated films with PDHPA. This study shows that the treated films at the pressure of 1 MPa can be used as suitable absorber layer to fabricate CdTe solar cell devices.