Analysis of structural, morphological and nano-mechanical properties of vacuum evaporated nanoscale CdTe and ZnS films

The structural, morphological, and nano-mechanical properties of vacuum evaporated cadmium telluride (CdTe) and Zinc Sulfide (ZnS) films had been studied. The films used for the fabrication of optoelectronic sensors in the infrared range. The films had been deposited by vacuum evaporation technique on Si (100) substrate. The X-ray diffractogram had indicated stable polycrystalline cubic structure with (111) preferential orientation for both films. The crystallite size, intrinsic stress, microstrain, and dislocation density values had been evaluated to be 17.5 nm, 0.09 GPa, 9.96, and 3.2 x 1011 lines/cm2, respectively, for CdTe film. While for ZnS film, the parameters had been estimated to be 15 nm, 0.49 GPa, 9.71, and 4.4 x 1011 lines/cm2, respectively. The Field Emission Scanning Electron Microscopy (FESEM) study had revealed homogeneous, dense, and defect free structure of the film. Compositional analysis had confirmed that the Te/Cd ratio 1.1 while S/Zn ratio 0.71 in the grown films. Atomic Force Microscopy (AFM) measurements had indicated smooth and uniform film with rms surface roughness of-0.96 nm. Hardness, Young's modulus, strain rate, and creep of the top layer (ZnS) had been evaluated by nanoindentation. The hardness of the ZnS film had evaluated to be 1.80-2.39 GPa, and Young's modulus evaluated to be 181-248 GPa, for a 50-100 mu N load. The outcome of the investigations endorsed the fact that the CdTe and ZnS thin films grown by the vacuum evaporation technique are suitable for the fabrication of optoelectronic devices.