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Studies on surface deformation of copper sulphide thin films by holographic interferometry technique
Abstract
Holographic interferometry technique used to study the surface deformation of electrodeposited copper sulphide thin films on stainless steel substrate is here presented. It is concerned with the formation and interpretation of fringe patterns, which appears when a wave generated at some earlier time and stored in a hologram is later reconstructed by interfering with comparison wave. The proposed technique uses double exposure holographic interferometry (DEHI) together with simple mathematical relation, which allows immediate finding of stress, mass deposited and thickness of thin film. It must be further noted that, fringe spacing changes with time of deposition as well as solution concentration. The structural study (XRD) is carried out for the confirmation.
... djurleite (Cu1.95S) and chalcocite (Cu2S) [5]. The crystal structure of these phases ranges from orthogonal to hexagonal [6]. ...
... djurleite (Cu1.95S) and chalcocite (Cu2S) [5]. The crystal structure of these phases ranges from orthogonal to hexagonal [6]. ...
In this study, synthesis of CuS thin films on soda lime glass (SLG) substrates has been investigated. The synthesis method is based on high vacuum post-sulphidation of Cu thin films deposited by rf. magnetron sputtering. Sputtering conditions have been optimized so as to reduce grain size for better diffusion of S atoms through grain boundaries. XRD pattern of the precursor Cu sample revealed fcc structure with an average crystallite size of 24 nm. Best sulphidation was obtained at 175 oC for 60 min. The crystallite size of CuS calculated from the dominant peak of (110) planes was approximately 48 nm while average grain size observed via SEM was about 400 nm. Raman spectroscopy confirmed CuS structure by scattering peaks at around 467-472 cm-1. Elemental mapping unveiled homogenous distribution of Cu and S atoms over the surface. According to EDS data, at% compositions of Cu and S were 51.6% and 48.4%, respectively. Moreover, SIMS investigation has demonstrated uniformity of S atoms through the thickness of CuS thin film. Although XRD, Raman, and EDS analysis have resulted in predominant formation of CuS structure, existence of Cu2S phase with a strong luminescence peak located at 1.8 eV was determined by PL spectroscopy.
... The recorded hologram of Cd 0.3 Zn 0.7 S thin films shows that as deposition time increases from 2 to 10 min, number of fringes on the substrate increases and the fringe width deceases as mentioned in Table 1 above [22]. Fig. 4 shows variation of fringe width with deposition time. ...
... Nanocrystalline copper sulfide (CuS NCs) is such a p-type semiconductor which regularly exhibits at least five stable phases with different Cu:S molar ratios (Cu x S). Copper sulphide forms five stable phases at room temperature: covellite (CuS), anilide (Cu 1.75 S), digenite (Cu 1.8 S), djurleite (Cu 1.95 S) and chalcocite (Cu 2 S) [2] with a crystal structure varying from orthogonal to hexagonal [3]. Copper sulfide films are interesting absorber materials with their film solar cells with ideal optical characteristics. ...
Raman spectroscopy and X-ray diffraction (XRD) methods were applied to determine the phase composition and crystal quality of CuS nanostructured film grown by spray pyrolysis. The film has polycrystalline structure with preferential growth along the (101) plane. The grain size for the film was found to be lower than 20 nm. The very sharp Raman peak around 470 cm(-1) in the high frequency region was identified as the S-S stretching mode of S-2 ions at the 4e sites. Other Raman peaks were around 266 cm(-1), 118 cm(-1) and 68 cm(-1) in the low frequency region due to CuS phase. Particles of nanometric size show low wavenumber vibrational modes that can be observed by Raman spectroscopy. Optical properties were obtained from UV-vis absorption, transmittance and reflectance spectra of the nanostructured CuS film. The optical constants of the film such as refractive index, extinction coefficient and, optical conductivity were investigated. The film was found to be p-type by using hot probe method.
In the present paper, the MnO 2 films have been deposited on stainless steel support by potentiostatic mode of electrodeposition at different times. The x-ray diffraction, Fourier transform infrared spectroscopy along with Energy-dispersive x-ray spectroscopy analysis confirmed formation of amorphous MnO 2 coating. The surface analysis by field emission scanning electron microscope indicated development of fractures with increasing film thickness. The in situ measurement of stress to the substrate and MnO 2 film thickness during deposition is performed by non-destructive double exposure digital holographic interferometry (DEDHI) technique. It was observed that the stress to the substrate decreases with increasing MnO 2 film thickness. This study opens application of DEDHI for non-destructive measurement using simple mathematical interpretation.
Copper sulfide (CuS) thin films were prepared on commercial glass substrates by Chemical Bath Deposition (CBD) method using solution of different copper salts at 50 °C temperature for seven hours. Different anions of copper salts that is crucial for the properties of the films affect the precipitation mechanism and growth rate. For this reason, the effect of the different copper salts on the properties of CuS thin films was investigated and discussed. The influence of the different copper salts in the chemical bath was determined by means of optical transmission of the thin films in the wavelength range of 400–1100 nm taken at room temperature. Next, using these data, the optical band gap values Eg, the extinction coefficient k, the refractive index n, and the real ε1 and imaginary parts ε2 of the dielectric constant were calculated. The crystallographic structure of CuS thin films were analyzed with an X-ray diffractometer (XRD). XRD analysis was revealed the polycrystalline and hexagonal phase of CuS thin films. The surface roughness of the films were measured by AFM. The surface roughness of the thin films was different despite the same deposition time.
The precise displacement measurement of cantilever beam could hardly be achieved because of the properties of cantilever beam such as flexibility, thinness and easy deformation. In the paper, the holographic double exposure interferometry is applied to record relative displacement field of the object under different load conditions, and therefore the interference fringe varies with the displacement of the object caused by different levels of load. A novel method of the fringe spacing measurement is introduced based on digital image processing. Meanwhile, the theoretical displacement distribution is calculated according to the numerical solutions of beams deflection curve. Numerical simulations are also carried out by finite element software ANSYS. The experimental results conform to the theoretical analysis completely; therefore, a new method to solve the problem of displacement measurement of cantilever beam is provided.
Holography is an interference method of recording the light waves diffracted by a subject illuminated with coherent light. Holographic interferometry is the most important and revolutionary application of holography. It is an extension of interferometric measurement technique in which at least one of the waves, which interfere, is reconstructured by hologram. It is concerned with the formation and interpretation of fringe patterns, which appear when a wave generated at some earlier time and stored in a hologram is later reconstructed by interfering with a comparison wave. The paper describes the use of holography in chemistry to study transport phenomena in transparent liquids. Diffusion is the movement of molecules due to their thermal energy under the influence of concentration gradient. we have employed DELHI technique for determining diffusion coefficient of 0.5 N sucrose solution. This technique resulted in producing good contrast fringes which are superior than reported earlier. The experimental results are compared with existing diffusion coefficient values and it is observed that there is good agreement with existing data.
During last three decades, successive ionic layer adsorption and reaction (SILAR) method, has emerged as one of the solution methods to deposit a variety of compound materials in thin film form. The SILAR method is inexpensive, simple and convenient for large area deposition. A variety of substrates such as insulators, semiconductors, metals and temperature sensitive substrates (like polyester) can be used since the deposition is carried out at or near to room temperature. As a low temperature process, it also avoids oxidation and corrosion of the substrate. The prime requisite for obtaining good quality thin film is the optimization of preparative provisos viz. concentration of the precursors, nature of complexing agent, pH of the precursor solutions and adsorption, reaction and rinsing time durations etc.
In the present review article, we have described in detail, successive ionic layer adsorption and reaction (SILAR) method of metal chalcogenide thin films. An extensive survey of thin film materials prepared during past years is made to demonstrate the versatility of SILAR method. Their preparative parameters and structural, optical, electrical properties etc are described. Theoretical background necessary for the SILAR method is also discussed.
Real-time holographic interferometry (RTHI) has occupied a prominent place in the study of various physical processes. This paper characterizes the main features of such methods, describes the apparatus developed for implementing them, and discusses experiments that use RTHI methods and apparatus.
Silver sulphide (Ag2S) thin films have been deposited on to stainless steel and fluorine doped tin oxide (FTO) glass substrates by the electrodeposition process, in potentiostatic mode using silver nitrate (AgNO3), sodium thiosulphate (Na2S2O3) as a precursor sources and Ethylene Diamine Tetra Acetic Acid (EDTA) was used as a complexing agent. The deposition potential of the compound was investigated by cyclic voltammetry. The structural and optical properties of the deposited films have been studied using X-ray diffraction (XRD) and optical absorption techniques, respectively. XRD studies reveal that the films are polycrystalline with monoclinic crystal structure. Optical absorption study shows the presence of direct transition with bandgap energy 1.1eV. The determination of thickness and stress of the Ag2S thin films was carried out by Double Exposure Holographic Interferometry (DEHI) technique.
Semiconducting stoichiometric copper sulphide (Cu2S) thin films were deposited using modified chemical deposition method. The preparative conditions such as concentration, pH of cationic and anionic precursors, adsorption, reaction and rinsing time durations, complextant, etc. were optimized to get stoichiometric Cu2S thin films. The structural, surface morphological, compositional, optical and electrical characterization were carried out with the help of X-ray diffraction (XRD), scanning electron microscopy (SEM), high resolution transmission electron microscopy (HRTEM), Rutherford back scattering (RBS), optical absorbance/transmittance, electrical resistivity and thermoemf studies. The films were found to be nanocrystalline. Absorbance of the film was high (104cm−1) with optical band gap of 2.35eV. The electrical resistivity was of the order of 10−2Ωcm with p-type electrical conductivity.
The growth of copper sulfide thin films by the successive ionic layer adsorption and reaction (SILAR) method at room temperature and normal pressure was studied. The CuS films were characterized by chemical analysis, XRD, SEM and UV spectroscopy. The growth rate of CuS was proportional to copper precursor concentration. The films were polycrystalline and showed no preferred orientation. The surface of the CuS thin films was rough compared with CdS films, which were used as buffer layer on ITO and glass substrates to enhance the weak adhesion of CuS to oxide surfaces.
Silver selenide (Ag2Se) thin film has been electrodeposited at room temperature from an aqueous acidic bath containing silver nitrate (AgNO3) and selenium dioxide (SeO2) as precursor salt with ethylene diamine tetra-acetic acid (EDTA) as a complexing agent. The electrodeposition of Ag2Se thin film was carried out by varying the time of deposition. The influences of preparative parameters on growth of Ag2Se thin film have been studied. This electrodeposited film has been characterized by X-ray diffraction (XRD) for their structural studies. Surface morphological study of Ag2Se thin film was carried out by scanning electron microscope (SEM). The determination of thickness and stress of the Ag2Se thin film was carried out by double exposure holographic interferometry (DEHI) technique. Band gap of Ag2Se thin film was calculated by using UV–vis spectrophotometer.
Holography is an interferometric method of recording the light waves diffracted by a subject illuminated with coherent light. Holographic interferometry (H.I.) is one of the most important applications of holography. It is concerned with the formation and interpretation of fringe patterns, which appears when a wave generated at some earlier time and stored in a hologram is later reconstructed by interfering with comparison wave. We report a technique, which uses double exposure holographic interferometry together with simple mathematical interpretation, which allow immediate finding of stress and thickness of thin film. We tested the same for different normalities of solutions. It was further noticed that the fringe spacing changes with solution concentration as well as time of deposition. The thin films are prepared using electrodeposition technique. It’s structural, morphological and optical study carried out by XRD, SEM, and UV–Vis–NIR spectrophotometer.