Search

In this report, ternary semiconducting NixBi2−xS3(x = 0.2 M and 0.5 M) thin films were synthesized in situ for the first time by a chemical bath deposition technique at different bath temperatures (60 °C, 70 °C and 80 °C). The effects of concentration and deposition temperature on the deposited films were studied by combining the results of structural, morphological, optical and electrical analyses. The growth of NixBi2−xS3 films with good crystalline nature and interconnected grain arrangement takes place due to increasing the concentration of Ni2+ ions in bismuth sulfide matrix. EDS result confirmed the stoichiometry of NixBi2−xS3 formation. Wettability test demonstrated that the surface of the film was hydrophilic in nature. The optical absorption spectra revealed that the bandgap Eg of the x = 0.5 M film deposited at 70 °C was about 1.36 eV. Current-voltage (I-V) characteristics of the x = 0.5 M film deposited at 70 °C were studied under X-ray radiation and dark condition. An X-ray detection sensitivity analysis showed that the detection sensitivity is optimum when the bias voltage applied across the film is low (~0.9 V). These findings reveal that the film with x = 0.5 M deposited at 70 °C can be used as an efficient low cost X-ray sensor. [ABSTRACT FROM AUTHOR]

Study on the optoelectronic characteristics of a cation-substituted nanostructure is a specific area of recent interest for a wide range of photonic applications. In the present work, AlxV2O5 (where x = 0, 5, 10 and 15%) nanoparticles were synthesized by a wet chemical-calcination process. X-ray diffraction study revealed the orthorhombic phase of 600 °C heat-treated pure and Al3+ substituted samples. The shifting of the XRD lines with the substitution of V2O5 suggests that Al3+ was successfully introduced into the V2O5 host lattice. The SEM and TEM images show that the pure and Al3+ doped V2O5 hierarchical architectures are formed of one-dimensional nanorods. Photoluminescence spectra demonstrated the increment in deformities revealed by the immensely enhanced green emission. DC conductivity studies were performed in the temperature range 30–130 °C and it was found that the activation energy (Ea) is higher for AlxV2O5 than for the undoped sample. The inherent current (I)–voltage (V) characteristics of pure V2O5 and AlxV2O5 junction diodes showed a nonlinear diode-like behavior. The transient photocurrent under illumination is higher than the dark current, indicating that the fabricated diodes behave as a photodiode. [ABSTRACT FROM AUTHOR]

Abstract: Copper indium disulphide (CuInS2) is an efficient absorber material for photovoltaic applications. In this work Zn (0.02 and 0.03M) doped CuInS2 thin films are (Cu/In=1.25) deposited onto glass substrates in the temperature range 300–400°C. XRD patterns depict, Zn-doping facilitates the growth of CuInS2 thin films along (112) preferred plane and other characteristic planes. Optical studies show, 90% of light transmission occurs in the IR regions; hence Zn-doped CuInS2 can be used as an IR transmitter. The absorption coefficient in the UV–vis region is found to be in the order of 104–105 cm−1. Optical band gap energies increase with increase of temperatures (0.02M – (1.93–2.05eV) and 0.03M – (1.94–2.04eV)). Well defined, broad Blue and Green band emissions are exhibited. Resistivity study reveals the deposited films exhibit semiconducting nature. Zn species can be used as a donor and acceptor impurity in CuInS2 films to fabricate efficient solar cells and photovoltaic devices. [Copyright &y& Elsevier]

Abstract: Copper indium disulfide (CuInS2) is an efficient absorber material for photovoltaic and solar cell applications. The structural, optical, photoluminescence properties and electrical conductivities could be controlled and modified by suitably doping CuInS2 thin films with dopants such as Zn, Sn, Bi, Cd, Na, N, O, P and As. In this work Zn (0.01M) doped CuInS2 thin films are (Cu/In=1.25) deposited on to glass substrates in the temperature range 300–400°C. It is observed that the film growth temperature, ion ratio (Cu/In=1.25) and Zn-doping affect structural, optical, photoluminescence and electrical properties of sprayed CuInS2 thin films. As the XRD patterns depict, Zn-doping facilitates the growth of CuInS2 thin films along (112) preferred plane and in other characteristic planes. The EDAX results confirm the presence of Cu, In, S and Zn in the films. The optical studies show, about 90% of light transmission occurs in the IR regions; hence Zn-doped CuInS2 can be used as an IR transmitter. The absorption coefficient (α) in the UV–visible region is found to be in the order of 104–105 cm−1 which is the optimum value for an efficient absorber. The optical band gap energies increase with increase of temperatures (1.66–1.78eV). SEM photographs reveal crystalline and amorphous nature of the films at various temperature ranges. Photoluminescence study shows that well defined broad Blue and Green band emissions are exhibited by Zn-doped CuInS2 thin films. All the films present low resistivity (ρ) values and exhibit semiconducting nature. An evolution of p-type to n-type conductivity is obtained in the temperature range 325–350°C. Hence, Zn species can be used as a donor and acceptor impurity in CuInS2 thin films to fabricate efficient solar cells, photovoltaic devices and good IR Transmitters. [Copyright &y& Elsevier]

Using chemical bath deposition (CBD) technique, CuBiS2 thin films of different bath temperature and deposition time were prepared on glass substrates. There is a blue shift in the PL spectrum of CuBiS2 thin films were observed. A strong emission peak is observed at 419 nm. The excitation wavelength was 209 nm. This effect may be related to the quantum effects. PL emission intensity increases with bath temperature and deposition time. The emission peak occurs at a higher wavelength than that of the absorption peaks. In fact, the peak emission wavelength is invariably shifted towards red end of spectrum compared to the peak of the absorption spectrum. This phenomenon is known as the Stokes shift. [ABSTRACT FROM AUTHOR]

Thin films of CdS of different thickness have been prepared on glass substrates in various temperatures by Chemical bath deposition. The thickness of the deposited film is measured by employing quartz crystal monitor method. The optical properties have been studied. The variation of band gap values of CdS thin film samples were found to be in the range of 2.16 to 2.45 eV. Electrical resistivity measurements were carried out in four-probe vander pavu geometry at room temperature. Resistivity of CdS thin films is about 108Ωcm. The micro structural parameters such as grain size, dislocation density and strain have been evaluated. The lattice parameter values 'a' and 'c' have been determined and is found to be 4.101Å and 6.68 Å respectively. [ABSTRACT FROM AUTHOR]

Bismuth sulphide thin films have been prepared onto amorphous glass substrates by chemical bath deposition method at bath temperature of 333K using bismuth nitrate, sodium thiosulphate and EDTA as complexing agent. The deposited films are characterized by X-ray diffraction and optical absorption. The effect of annealing on the structural and optical properties is studied. [ABSTRACT FROM AUTHOR]

Cadmium Sulphide thin films have been deposited on to well cleaned glass substrate in a vacuum of 10-6 Torr. The thickness of the films has been determined by quartz crystal monitor method. CdS thin film of lower thicknesses has amorphous structure and higher thickness has polycrystalline nature with cubic structure. The structural parameters such as interplannar distance (d), lattice constant (a), grain size (D), dislocation density and microstrain have been evaluated. The optical properties have been studied in the range of wavelength 300-900nm. It is observed that band gap energy is inversely depended on film thickness. The electrical resistivity measurements were performed at room temperature by four probe method and it shows CdS films with high ressitivity. [ABSTRACT FROM AUTHOR]

Abstract: Copper indium disulphide (CuInS2) is an absorber material for solar cell and photovoltaic applications. By suitably doping CuInS2 thin films with dopants such as Zn, Cd, Na, Bi, Sn, N, P and As its structural, optical, photoluminescence properties and electrical conductivities could be controlled and modified. In this work, Sb (0.01mole (M)) doped CuInS2 thin films are grown in the temperature range 300–400°C on heated glass substrates. It is observed that the film growth temperature, the ion ratio (Cu/In=1.25) and Sb-doping affects the structural, optical and photoluminescence properties of sprayed CuInS2 films.The XRD patterns confirm that the Sb-doping suppresses the growth of CuInS2 polycrystalline thin films along (112) preferred plane and in other characteristic planes. The EDAX results confirm the presence of Cu, In, S and Sb. About 60% of light transmission occurs in the wavelength range 350–1100nm. The absorption coefficient (α) is found to be in the order of 105 cm−1. The band gap energy increases as the temperature increases from 300–400°C (1.35–1.40eV). SEM photographs depict that large sized crystals of Sb-doped CuInS2 (1μm) are formed on the surface of the films. Well defined sharp blue and green band emissions are exhibited by Sb-doped CuInS2 thin films. Defects-related photoluminescence emissions are discussed. These Sb-doped CuInS2 thin films are prepared by the cost effective method of spray pyrolysis from the aqueous solutions of CuCl2, InCl3, SC(NH2)2 and SbCl3 on heated glass substrates. [Copyright &y& Elsevier]

Abstract: Copper indium disulphide (CuInS2), is a good absorber material for photovoltaic applications. In this work, CuInS2 is deposited by chemical spray pyrolysis on heated glass substrates. It is observed that the film growth temperature and the ion ratio Cu/In affects the structural and optical properties of CuInS2 thin films. This paper presents the effect of temperature on the growth (for the ion ratio Cu/In=1.25), optical and photoluminescence properties of sprayed CuInS2 films. The XRD patterns confirm the well defined single phase composition of CuInS2 films grown from 300 to 350°C (at Cu/In=1.25) as optimum temperature for depositing well defined crystallites along (112) oriented CuInS2 thin films with chalcopyrite structure. D2d point symmetry group is associated with the CuInS2 crystallites with energy gap of 1.53eV at room temperature. The chemical nature and the presence of additional phases are discussed based on the EDAX measurements. The absorption coefficient of sprayed CuInS2 films is found to be in the order of 105–106 cm−1 in the UV–visible region and the optical band gap decreases with increase in temperature. Defects-related photoluminescence properties are also discussed. CuInS2 polycrystalline films are prepared by the cost effective method of spray pyrolysis from the aqueous solutions of copper (II) chloride, indium (III) chloride and thiourea for synthesis on heated glass substrates. [Copyright &y& Elsevier]

Abstract: Single-crystalline lead bismuth sulphide (PbBiS2) thin films were successfully deposited on glass substrate by chemical bath deposition technique. The films were characterised by X-ray diffraction (XRD), scanning electron microscope (SEM), energy dispersive analysis of X-ray (EDAX) and UV–VIS absorption spectroscopy. X-ray diffraction analysis indicates the PbBiS2 thin films were in single-crystalline phase with orthorhombic structure. EDAX and SEM observations confirm the formation of PbBiS2 and spherical nature. The absorption spectra of the films indicated that the compound is a direct band gap material; the energy band gap is about 1.97eV. These results indicate that the PbBiS2 prepared by chemical bath deposition technique is a promising candidate for photovoltaic device applications. [Copyright &y& Elsevier]