Characterization of Vacuum Evaporated Polycrystalline Cd0.96Zn0.04Te Thin Films by XRD, Raman Scattering and Spectroscopic Ellipsometry

Abstract

Cd0.96Zn0.04Te thin films are deposited onto well cleaned glass substrates (Corning 7059) kept at room temperature by vacuum evaporation and the films are annealed at 423 K. Rutherford Backscattering Spectrometry and X‐ray diffraction techniques are used to determine the thickness, composition and crystalline structure and grain size of the films respectively. The films exhibited zinc blende structure with predominant (111) orientation. The surface morphology of the films is studied by Atomic Force Microscopy. The rms roughness of the as‐deposited films is 3.7 nm and on annealing the films at 423K, the rms roughness value decreases to 3.4 nm. The Raman spectra of the Cd0.96Zn0.04Te films are recorded at room temperature to study lattice vibrations and their interactions with other excitations. The intensity of the peak increases and the FWHM decreases on annealing the films. The pseudodielectric‐function spectra, ε(E) = ε1(E) + i ε2(E), of polycrystalline Cd0.96Zn0.04Te thin films in the 1.3 ‐ 5.5eV photon energy range at room temperature are measured by spectroscopic ellipsometry. The measured dielectric function spectra reveal distinct structures at energies of the E1, E1+Δ1 and E2 critical points are due to interband transitions.

Photoluminescence of Nanocrystalline CdS Thin Films Prepared by Chemical Bath Deposition

“…Figure 2 shows the crystallite size of the CdS thin films as a function of the film thickness. It initially increases as the film thickness increases, and it is nearly constant If the crystallite size is known, the dislocation density δ of the CdS thin film is determined using the relation [16]: (2) where D is the crystallite size of the CdS thin film. Figure 3 shows the dislocation density of the CdS thin films as a function of the deposition time.…”

Optical Constants and Dispersion Parameters of CdS Thin Film Prepared by Chemical Bath Deposition

“…Spectroscopic ellipsometry (SE) is a useful and nondestructive tool to obtain the optical constants of thin films. The complex dielectric function, optical constants, and microstructure of thin films are studied from spectroscopic ellipsometry [6,9,10,[18][19][20][21]. The optical constants of refractive index, extinction coefficient, normal-incidence reflectivity, and absorption coefficient in thin films are obtained using SE data of the complex dielectric function [18,19,22].…”

“…The complex dielectric function, optical constants, and microstructure of thin films are studied from spectroscopic ellipsometry [6,9,10,[18][19][20][21]. The optical constants of refractive index, extinction coefficient, normal-incidence reflectivity, and absorption coefficient in thin films are obtained using SE data of the complex dielectric function [18,19,22]. The dispersion of refractive index can be analyzed using the WempleDiDomenico single-oscillator model (W-D model) [23], in which the refractive index n in the low absorption region is expressed using the oscillator energy, dispersion energy, and photon energy.…”

Thickness dependence on structural, dielectric and AC conduction studies of vacuum evaporated Sr doped BaTiO3 thin films

“…From the table it has been observed that the grain size increases with increase in thickness whereas the strain and the dislocation density decrease with the increase in thickness. Due to the increase in grain size with film thickness, the defects in the lattice are decreased, which in turn reduce the internal micro strain and dislocation density/or the columnar grain growth is increased [18].…”