Structural, optical and nanomechanical properties of (1 1 1) oriented nanocrystalline ZnTe thin films

M. S.R.N. Kiran, S. Kshirsagar, M. G. Krishna, Surya P. Tewari
2010 European Physical Journal : Applied physics  
Structural, optical and nanomechanical properties of nanocrystalline Zinc Telluride (ZnTe) films of thickness upto 10 microns deposited at room temperature on borosilicate glass substrates are reported. X-ray diffraction patterns reveal that the films were preferentially oriented along the (1 1 1) direction. The maximum refractive index of the films was 2.74 at a wavelength of 2000 nm. The optical band gap showed strong thickness dependence. The average film hardness and Young's modulus
more » ... g's modulus obtained from loaddisplacement curves and analyzed by Oliver-Pharr method were 4 and 70 GPa respectively. Hardness of (1 1 1) oriented ZnTe thin films exhibited almost 5 times higher value than bulk. The studies show clearly that the hardness increases with decreasing indentation size, for indents between 30 and 300 nm in depth indicating the existence of indentation size effect. The coefficient of friction for these films as obtained from the nanoscratch test was ∼0.4. Experimental ZnTe thin films of different thicknesses were deposited by evaporating pure ZnTe compound (99.995%, supplied by Aldrich Chemicals) onto cleaned borosilicate glass substrates at ambient temperature. The ultimate vacuum of about 6 × 10 −6 mbar was reached using a diffusion pump backed by a rotary pump. The glass substrates were cleaned using detergent solution, followed by multiple rinsing in distilled water to remove traces of detergent. The substrates were then cleaned in an ultrasonic cleaner for 15 min and subsequently dried in flowing hot air. Article published by EDP Sciences
doi:10.1051/epjap/2010071 fatcat:7zqc3ievpzh6hlpaxkzb3tpzsu