Optical properties of CdS:Pb thin layer deposited on glass substrate (original) (raw)
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Chalcogenide Letters
Cadmium sulfide polycrystalline thin films of different thickness were deposited on ultrasonically cleaned glass substrates by thermal evaporation technique in a vacuum of about 2х10 torr. X-ray diffraction and SEM (scanning electron microscope) were used to characterize the thin films. X-ray diffraction study showed that, all the films have the hexagonal wurtzite structure, with lattice constants a=b=4.142, c=6.724A˚. Crystallite sizes calculated from Scherrer relation are in the range of 49-68 nm and the grain size of the thin films are observed to increase with the increase in the thickness of the sample. The optical properties of the polycrystalline thin films were investigated by the UV-VIS-NIR spectroscopy. The band gap of the thin films is found to be direct allowed transition and increases with the increase of thickness of films in the range of 2.35- 2.46 eV. Extinction coefficient k showed oscillatory behavior in lower band edge region. The CdS polycrystalline thin films ar...
Investigation of Optical Properties of Cadmium Sulfide (CdS) Thin Films by Chemical Bath Deposition
Thin films of CdS were deposited on glass substrates using a chemical bath deposition technique from aqueous solutions of Cadmium sulfate (CdS) and thiouria. The films grown from the bath are uniform and adherent, have a high transmittance in the visible region. The CdS films properties studied include optical transmission, optical constant, dielectric constant, optical conductivity, and band gaps. The films in this study produced fairly high transmission (> 86% between 500 and 900). Band gaps of (2.4 eV) for direct transition were obtained. Such films could be used as photocells and other photoconductive devices, thin film transistors and diodes, piezoelectric ultrasonic transducers and amplifiers, piezoelectric acoustic resonators and electron beam-pumped lasers.
A Simple and cost effective chemical bath deposition process has been employed for the preparation of Cd 1-x Pb x S (x = 0.00, 0.20, 0.40, 0.60, 0.80, 1.00) thin films. Cadmium sulphate, lead sulphate and thiourea were used as the basic source materials. The effect of various preparative parameters such as bath composition, pH of the reaction solution, deposition temperature and time, speed of the substrate rotation and the complexing agent on growth process is studied and these parameters are optimized for good quality films. The colour of the 'as-deposited' thin films has changed from orange yellow to black as the composition parameter x changed from 0 to 1. The film thickness is found to be increased with increasing the composition parameter x from 0 to 1. The X-ray diffraction (XRD) studies revealed that films are polycrystalline in nature and exhibit both cubic and hexagonal structure for pure CdS but only cubic phases for pure PbS film. The energy dispersive analysis b...
Al-Mustansiriyah Journal of Science
In this research , we study the effect of substrate temperature (423K and 473K) on structural and optical properties for thin films of cadmium sulfide (CdS) by evaporation thermal deposition method on glass substrates and the thickness was about (390nm).XRD analysis showed that CdS thin films prepared at (423K and 473K) are single crystal and have preferred orientation along (002).The grain size was found to be increased with increasing substrate temperature, in addition, the atomic force microscopy(AFM) an increase in root mean square (RMS) with an increase in substrate temperature. The absorbance and transmittance spectra have been recorded in the range off wave length(400-800nm), and it was found that the transmittance decreases with increasing substrate temperature, while the optical band gap decreases from (2.4-2.2ev)for allowed direct transition. CdS thin films should further investigated for application towards the fabrication of solar cells.
Semiconductors, 2012
Cd 1−x Pbx S thin films were prepared by spray pyrolysis technique onto glass substrate at 300 • C temperatures. The prepared films were characterized elemental, structural and optical properties by energy dispersive X-ray, scanning electron microscopy, X-ray diffraction and UV-VIS spectrophotometer. Energy dispersive X-ray confirmed the presence of Cd, S and Pb in the films. SEM images show that the deposition covered the substrate well uniformly and incorporation of Pb. Crystal stucture was found hexagonal and the estimated grain size was lies in between 9 to 49 nm. The optical band gap was decreased from 2.43 to 2.07 eV.
Effect of Pb incorporation on energy band gap of CdS thin films
Journal of Ovonic Research
The thin films of Cd 1-x Pb x S (0 ≤ x ≤ 1) have been deposited onto clean glass substrates by economical bath deposition technique. The deposition parameters were optimized to obtain good quality thin films. The absorption spectra of these films have been recorded using spectrophotometer. The energy band gap (E g ) and absorption coefficient (α) has been determined using these spectra. It is found that the band gap decreases with increase in Pb concentration. It is observed that energy band gap is varied from 2.47 eV (CdS) to 0.49 eV (PbS) as composition parameter 'x' increased from 0 to 1. The nature of the band gap has also determined in this paper.
The effect of Cd substitution in PbS thin film on the optical properties
Journal of University of Anbar for Pure Science
Thin films of CdxPb1-x S were prepared by chemical spray pyrolysis with (x=0.6 , 0.7 , 0.8 , 0.9 , 1) .The optical properties of prepared thin films were studied by UV-VIS spectrophotomer. From the measurement of absorption and transmission , the optical parameters and the optical energy gap (Eg) were calculated .The optical energy gap (Eg) was increased with increasing the value of Cd from 1.2 eV when x=0.6 to 2.4 eV when x=1. The maximum value of refractive index (n) is equal to 2.5 and the maximum value of extinction coefficient is varied between 0.2 to 0.45 depending on the value of x. The film with x=0.7 was doped by Ag in the ratio 1% ,3% and 5%. The film after dopping have a direct energy gap also and the value of Eg were increased with increasing (Ag) ratio , these values increased from 1.2 eV for absent Ag to 1.74 eV for 5% Ag .
Thin films of cadmium sulphide have been successfully deposited by chemical bath deposition (CBD) technique using a mixed aqueous solution of cadmium sulphate, thiourea, and triethylamine. The films were characterized using a variety of techniques. Powder X-ray diffraction analysis shows that the as-deposited thin film has the hexagonal (wurtzite) structure. Scanning electron microscope (SEM) micrographs show the film surface consists of clusters with a globular surface morphology. Energy dispersive X-ray diffraction (EDAX) analysis confirmed the film to be consistent with the formation of cadmium sulphide on silica glass slide. The band gap, determined from optical absorption spectroscopy, was 2.42 eV which is consistent with other published results.
Journal of New Materials For Electrochemical Systems, 2010
Present work focuses on the preparation and characterization of IInVI thin film semiconductor compound Cadmium Sulfide (CdS), commonly used as window layer in polycrystalline thin-film photovoltaic cells. CdS thin films were prepared by chemical bath deposition (CBD) in six different thicknesses and subjected to heat treatment at five different temperatures in nitrogen atmosphere, in order to find the appropriate film for perfect window layer in copper indium diselenide (CIS)/CdS photovoltaic cells. Structural and optical characterizations were carried out by X-ray diffraction and UV-VIS-NIR spectrometer respectively. Both the Hawleyite (cubic) and Greenockite (hexagonal) phases were observed, the latter being most predominant. Films show good transmittance in visible region and the band gap was found to decrease with the increase in thickness and annealing temperature.
2009
Highly crystalline and transparent cadmium sulphide films were fabricated at relatively low temperature by employing an inexpensive, simplified spray technique using perfume atomizer (generally used for cosmetics). The structural, surface morphological and optical properties of the films were studied and compared with that prepared by conventional spray pyrolysis using air as carrier gas and chemical bath deposition. The films deposited by the simplified spray have preferred orientation along (1 0 1) plane. The lattice parameters were calculated as a = 4.138 Å and c = 6.718 Å which are well agreed with that obtained from the other two techniques and also with the standard data. The optical transmittance in the visible range and the optical band gap were found as 85% and 2.43 eV, respectively. The structural and optical properties of the films fabricated by the simplified spray are found to be desirable for opto-electronic applications.