Structural and optical studies of laser ablated nanostructured CdTe thin films

Nanometer thin CdTe films were deposited on BK7 glass substrates using pulsed laser deposition technique in vacuum of 4.0 x 10(-6) mbar. The as grown films were then annealed in air at different temperatures. These films were characterized by X-ray diffraction, optical and atomic force microscopy techniques for phase identification, structure and morphology. The optical properties of the films were measured using transmission and spectroscopic ellipsometry measurements. The chemical composition, thickness and interface of the substrate and films were studied by Rutherford backscattering spectroscopy. CdTe thin films prepared by this process are found to have single phase with cubic zinc blende structure. The growth occurred in the (111) preferential direction of the cubic structure. The optimized growth for crystalline and stoichiometric films possessing good structural and optical properties were achieved after annealing in air at 300 degrees C. In the present study efforts have been made to correlate the optical properties of the CdTe thin films with the corresponding microstructural features associated with these films.