Effect of annealing on the structural and optical properties of indium-diffused Cd_0.7Zn_0.3Se thin films

Abstract

Cadmium zinc-selenide (Cd0.7Zn0.3Se) thin films were deposited on the ITO substrate using chemical bath deposition techniques by optimizing the deposition parameters. The as-deposited films were annealed in air at 200, 300 and 400 °C for 1 h. The composition, surface morphology and structural properties of the as-deposited and annealed Cd0.7Zn0.3Se thin films were studied using x-ray photoelectron spectroscopy, scanning electron microscopy and x-ray diffraction techniques. The as-deposited films exhibited the hexagonal phase of CdSe and ZnSe. The films annealed at 200 °C showed the dominant cubic phase of CdSe and the hexagonal phase of ZnSe. However, the cubic structure of Cd0.7Zn0.3Se was transformed into a hexagonal structure after annealing at 300 and 400 °C. The lattice parameter a for the cubic structure was 6.0865 Å, whereas for the hexagonal structure a varied from 4.3035 to 4.2938 Å and c varied from 7.0916 to 6.9868 Å. The optical absorption spectra were recorded within the range 350–800 nm. The optical band gaps were 2.08 eV, 2.03 eV, 1.91 eV and 1.72 eV for the as-deposited films and those annealed at 200 °C, 300 °C and 400 °C, respectively. The drastic decrease in the optical band gap at 300 and 400 °C was due to the indium diffusion into the Cd0.7Zn0.3Se matrix.

Microstructure and optical studies of electron beam evaporated ZnSe1−xTex nanocrystalline thin films

“…Additionally, the diffraction peak observed at 2Â ≈ 27.72 • becomes very strong indicating that the structure of the films was preferentially oriented along the crystallographic plane (1 1 1) as the annealing temperature increases. The annealing effects on the structure properties of the as deposited films agree with the thermal effects reported for other materials [32,33]. …”

Study of Structural, Morphological and Compositional Characteristics of Vacuum Deposited Zn0.75cd0.25se Thin Films

“…Initially ampoule of CdSe were formed, then mixed Zinc core material in given proportion and fused to very high temperature in quartz tube for uniform mixing of Zn, and CdSe to form ternary Zn 0.75 Cd 0.25 Se compound. Thin films of ZnxCd1-xSe were prepared by vacuum evaporation technique on glass substrate [8]. Then Zn 0.75 Cd 0.25 Se compound was grinded to get fine powder and placed in molybdenum boat for evaporation.…”

“…The low tension (LT) supply for evaporation source is obtained from a 230V input transformer by means of parallel connections in the secondary side of the transformer [10]. The Zn 0.75 Cd 0.25 Se samples of different thicknesses (1000 Å and 2500 Å) were deposited under almost same environment [8,11]. The thickness monitor model no.…”

Deposition of Cadmium doped Zinc Selenide Thin Films and its Characteristics

“…The relation between the absorption coefficient (α) and the incident photon energy (hν) is expressed as: αhν = A (hν -E g ) n where Eg is optical bandgap, A is a constant, n is a factor that determines the nature of transition. [16] Fig. 6 shows a graph of (αhν) 2 against (hν) for various x-parameters.…”