ROLE OF SUBSTRATE TEMPERATURE ON NANAOCRYSTALLISATION OF CdTe THIN FILMS

In the present investigation, nanocrystalline Cadmium Telluride (CdTe) thin films are deposited on glass substrates by thermal evaporation method. The films are deposited at various substrate temperatures of 573 K, 623 K, 673 K and 723 K. Structural characterization is carried out using X-ray diffraction (XRD) technique. XRD studies reveal nanocrystalline nature of the films. Scanning Electron Microscopy (SEM) is employed to investigate the surface morphology. SEM studies indicate that the nanograin formation begins at 573 K. However, increase in substrate temperature leads to grain agglomeration. The optical characterization is carried out using UV-Vis spectrophotometer. It is observed that the bandgap value is dependent on substrate temperature. All the experimental results indicate that the substrate temperature plays a major role in nanocrystallisation of CdTe thin films. This paper aims at studying the role of substrate temperature in CdTe nanopahse formation.