Hussein Hakim Abed, Hayder M. Abduljalil, Mudar Ahmed Abdulsattar

Abstract

The CdSe nanocrystalline thin films were fabricated on different substrates (silicon, indium tin oxide and glass) with different thicknesses (225, 250, and 300) nm by the pulsed laser deposition (PLD) technique. These thin films were characterized by the structural and optical measurements. From the X-ray diffraction (XRD), it was found that the thin films had hexagonal wurtzite structure. Crystallite size of the thin films increased from 13.56 nm to 21.368 nm with the increased thickness from 225nm to 300 nm. The atomic force microscopy images showed that the surface topography of the thin films got more homogeneity with the increased thickness. Optical properties have been performed by investigating the transmittance spectra in the spectral region (300–700) nm, and it was found that the thin films had the transmittance which increased with the increased wavelengths in the visible region, and the edge energy gap shifted from 1.8 eV to1.7 eV with the increased thickness from 225 nm to 300 nm, making the thin films suitable to be used in the optoelectronic and solar cell applications. The resistance of thin films was changed with the relative humidity, and their sensitivity was increased with the increased grain size and thickness, making CdSe thin films suitable to be used as a humidity sensor.