R. Zarei Moghadam, M.h. Ehsani, H. Rezagholipour Dizaji, M.r. Sazideh,
Volume 15, Issue 3 (September 2018)
Abstract
In this work, Cadmium Telluride (CdTe) thin films were deposited on glass substrates at room temperature by vacuum evaporation technique. The deposited CdTe thin films were characterized by X-ray diffraction, UV-Visible spectroscopy and Field emission scanning electron microscope (FESEM) techniques. Structural studies revealed that the CdTe films deposited at various thicknesses are crystallized in cubic structure. The results showed the improvement of the film crystallinity upon grain size increment. Optical constants such as refractive index (n), extinction coefficient (k), real and imaginary parts of dielectric constant, volume energy loss function (VELF), and surface energy loss function (SELF) were calculated using UV-Vis spectra. In addition, band gap and Urbach energies were calculated by Tauc and ASF methods. The band gap energy of the specimens was found to decrease from 1.8 to 1.4eV with increasing the thickness of films. The absorption coefficient, computed and plotted versus the photon energy (hν) and tailing in the optical band gap, was observed which is understood based on Urbach law. Urbach energy variation from 0.125 to 0.620 eV in the samples with higher thicknesses is concluded.
M. Minbashi, R. Zarei Moghadam, M. H. Ehsani, H. Rezagholipour Dizaji, M. Omrani,
Volume 16, Issue 3 (September 2019)
Abstract
Zigzag ZnS thin films prepared by thermal evaporation method using glancing angle deposition (GLAD) technique. ZnS films with zigzag structure were produced at deposition angles of 0˚, 60˚ and 80˚ at room temperature on glass substrates. Surface morphology of the films w::as char::acterized by using field emission scanning electron microscopy (FESEM). The optical properties of the specimens were investigated by using UV-Vis spectroscopy technique. To characterize the porosity of the simulated structures, the PoreSTAT software which analyses the NASCAM software was employed. The optical transmissions of the samples were calculated by using NASCAM optics package. The simulation results are completely in agreement with the experimental results.
