Fabrication and characterization of Zinc Telluride (ZnTe) thin films grown on glass substrates (original) (raw)
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Journal of Engineering Technology and Applied Physics
ZnTe bilayer thin films were deposited onto soda-lime glass by a thermal vacuum evaporation technique using the NANO 36 thermal evaporator under a vacuum pressure of 2.9 x 10-5 torr. The optical characteristics of the film were measured using an AVANTEX UV spectrophotometer in the wavelength range from 239.534 nm to 999.495 nm. Also, the electrical characteristics of the thin films were investigated using KEITHLEY four-point probe techniques. The investigation of the optical properties of the thin films as-deposited and annealed at different temperatures showed high transmission in the NIR region with good absorption in the visible and UV regions. The extrapolated band gap energies were 2.60 eV and 3.20 eV for annealed and as-deposited samples, respectively. electrical resistivity decreased as the annealing temperature increases. The images of the film as-deposited and on annealing have a uniform distribution on the glass slides.
Property elucidation of vacuum-evaporated zinc telluride thin film towards optoelectronic devices
Sādhanā, 2017
A thermal vacuum evaporation system has been used to deposit zinc telluride (ZnTe) thin film on glass substrate in order to investigate the structural, morphological, optoelectronic and electrical properties of the deposited film. The deposited film has been characterised by X-ray diffraction (XRD), atomic force microscopy (AFM), and UV-VIS-NIR spectrophotometer. The polycrystalline and cubic structure of the sample has been confirmed by XRD. The order parameter(s), which determines the crystallinity and good environmental stability of the sample, has been obtained for the peak (1 1 1) to peak (2 0 0) and is found to be 0.83. The XRD patterns and Bragg's law have been examined to determine the microstructural parameters (lattice parameter, inter-planar spacing, crystallite size, number of crystallites per unit area, strain, dislocation density) of the investigated film. Optical properties (transmittance, absorbance, refractive index, absorption coefficient, extinction coefficient, optical density) of ZnTe thin film were extensively studied in incident photon energy range of 0.5-3.5 eV, where direct optical transition has been obtained with a band gap of 2.63 eV. The surface morphology of the evaporated ZnTe thin film has been checked by AFM.
Journal of Crystal Growth, 2011
ZnTe thin films were deposited by the two-source evaporation technique on amorphous glass substrate. The deposited films were annealed under nitrogen ambient pressure. The resistivity of the film annealed under nitrogen pressure of 100 mbar was found to be less than that of as-deposited film by more than four orders of magnitude. The films structures were characterized by X-ray diffraction (XRD) and scanning electron microscope (SEM). The films' thickness and the optical properties such as refractive index, absorption coefficient and optical band gap of the films were determined from transmittance spectra in the wavelength range of 400-2000 nm. The dark electrical conductivity of the films was studied as a function of temperature to determine the DC conductivity activation energy of the films.
OPTICAL AND ELECTRICAL CHARACTERISTICS OF VACUUM EVAPORATED ZINC TELLURIDE THIN FILMS
IASET, 2020
These films of ZnTe compound of varying thickness ranging from 191.3 nm to 248.4 nm have been deposited by vacuum evaporation technique on the clean glass substrates. Optical method (Tolansky method) was employed to measure the thickness of the deposited thin films. The optical properties of the ZnTe thin films were investigated by UV-VIS spectrophotometer and the electrical resistivity have been studied as a function of thickness by Four Probe Kit. The results of all these studied parameters are presented and discussed in this paper.
Zinc Telluride Thin Films: A Review
Asian Journal of Chemistry
Extensive research has been carried out on the deposition and characterization of polycrystalline thin films by several researchers [1-32]. These materials are used in optical instruments, solar cells, telecommunications terminals, in-vehicle equipment, traffic lights, magnetic films, diamond films, microelectronic devices, solar selective coatings, sensor devices, optical mass memories and superconducting films. In recent years, binary semiconductor material such as zinc telluride has been studied by many scientists. Recent investigations have shown that zinc telluride thin films show absorption in the spectrum range from visible to near infrared (as widely reported in the literature). The II-VI (ZnTe) compound semiconductors have a direct transition at 2.26 eV. Therefore, ZnTe is capable of green light emission at 550 nm, i.e. in spectral region corresponding to the maximum sensitivity of the human eye. This makes ZnTe an appealing candidate for the production of bright light-emitting diodes and diode lasers. There are several reports available on the growth of zinc telluride thin films by different deposition methods such as electro-deposition method [33-35], closed space sublimation technique [36,37], screen printing technique [38], spray pyrolysis [39], radio frequency magnetron sputtering [40], thermal evaporation [41], electron beam evaporation [42], physical vapour deposition [43] and molecular beam epitaxy [44]. Each technique has strengths and weaknesses as described by researchers.
2012
ZnTe thin films were prepared by Stacking of elemental (Zn and Te) layers (SEL) followed by inert gas annealing. The optical parameters were calculated from the transmission spectra. The bandgap of the annealed samples was found between 1.95 eV and 2.06 eV. The change in film thickness after annealing was observed using cross sectional SEM image of the annealed samples. The surface morphology of the annealed Te/Zn stack was also analyzed and observed as very smooth, compact and dense surface. The prepared film was Zn rich evidenced by EDAX. The observed result encourages in pursuing the SEL method for the preparation of compound semiconductor from II-VI group materials.
Zinc telluride films by photoenhanced metalorganic chemical vapor deposition
Journal of Electronic Materials, 1991
Polycrystalline films of zinc telluride (ZnTe) have been deposited on glass and conducting semiconductor coated glass substrates at 270~176 C by photoenhanced metalorganic chemical vapor deposition (PECVD) using the reaction of dimethylzinc (DMZn) or diethylzinc (DEZn) and diisopropyltellurium (DIPTe) in hydrogen under atmospheric pressure. The deposited films are always of p-type conductivity. Their properties are affected by the DMZn/DIPTe or DEZn/DIPTe molar ratio in the reaction mixture. The optimum DMZn/DIPTe ratio has been found to be approximately 0.9 on the basis of the open-circuit voltage of ZnTe/CdS heterojunctions and photoconductivity measurements. Without intentional doping, the deposited films are of high resistivity (>107 ohm-cm) at room temperature, and the resistivity of these films has been controlled by using arsine as a dopant. The structural, optical, and electrical properties of ZnTe films have been characterized.
STRUCTURAL, ELEMENTAL COMPOSITIONS AND OPTICAL PROPERTIES OF ZnTe:V THIN FILMS
Vanadium doped zinc telluride (ZnTe:V) thin films of various thicknesses for a particular composition of 2.5wt% V were deposited onto glass substrates by e-beam evaporation technique in vacuum at a pressure of 8×10 -4 Pa. The deposition rate of the ZnTe:V films was maintained at 2.05 nms-1. The optical properties of ZnTe:V thin films for different film thicknesses have been studied in detail. Structural study of the films was performed by x-ray diffraction technique and it was found that the films are mixed crystalline in nature. Surface morphological study was done by using SEM technique. EDAX method was also used to determine the elemental composition in deposited thin films. The optical properties of as-deposited and annealed ZnTe:V films for different thicknesses were studied in the wavelength range 300 < λ < 2500 nm, respectively. For both types of samples, the values of the Urbach tail energy, optical band gap, refractive index, extinction coefficient and real part of di...
OPTICAL AND ELECTRICAL PROPERTIES OF ZnTe THIN FILMS USING ELECTRODEPOSITION TECHNIQUE
Zinc Telluride (ZnTe) thin films have been successfully deposited on a glass substrate Fluorine Tin oxide (FTO) by electrodeposition technique. The absorbance was measured using M501 UV-visible spectrophotometer in the wavelength range of 200-900nm. Zinc Telluride (ZnTe) thin films were investigated at room temperature. Optical absorption study showed that ZnTe films were of indirect band gap type semiconductor with band gap energy of 2.2-2.4eV.