Polycrystalline zinc oxide (ZnO) thin films have been deposited at 450°C onto glass and silicon substrates by pulsed laser deposition technique (PLD). The used source was a KrF excimer laser (248 nm, 25 ns, 5 Hz,...Polycrystalline zinc oxide (ZnO) thin films have been deposited at 450°C onto glass and silicon substrates by pulsed laser deposition technique (PLD). The used source was a KrF excimer laser (248 nm, 25 ns, 5 Hz, 2 J/cm2). The effects of glass and silicon substrates on structural and optical properties of ZnO films have been investigated. X-ray diffraction patterns showed that ZnO films are polycrystalline with a hexagonal wurtzite—type structure with a strong (103) orientation and have a good crystallinity on monocrystalline Si(100) substrate. The thickness and compositional depth profile were studied by Rutherford Backscattering spectrometry (RBS). The average transmittance of ZnO films deposited on glass substrate in the visible range is 70%.展开更多
Cu(In, Al)Se2 thin films were prepared by electrodeposition from the aqueous solution consisting of CuCl2, InCl3, AlCl3 and SeO2 onto ITO coated glass substrates. The as-deposited films were annealed under vacuum for ...Cu(In, Al)Se2 thin films were prepared by electrodeposition from the aqueous solution consisting of CuCl2, InCl3, AlCl3 and SeO2 onto ITO coated glass substrates. The as-deposited films were annealed under vacuum for 30 min at temperature ranging between 200°C and 400°C. The structural, composition, morphology, optical band gap and electrical resistivity of elaborated thin films were studied, respectively using x-ray diffraction, energy dispersive analysis of x-ray, scanning electron microscopy, UV spectrophotometer and four-point probe method. The lattice constant and structural parameters viz. crystallite size, dislocation density and strain of the films were also calculated. After vacuum annealing, x-ray diffraction results revealed that all films were polycrystalline in nature and exhibit chalcopyrite structure with (112) as preferred orientation. The film annealed at 350°C showed the coexistence of CIASe and InSe phases. The average crystallite size increases linearly with annealing temperature, reaching a maximum value for 350°C. The films show a direct allowed band gap which increases from 1.59 to 1.78 eV with annealing temperature. We have also found that the electrical resistivity of films is controlled by the carrier concentration rather than by their mobility.展开更多
The work reported in this paper aims at a better understanding of the magnetic doping effects on the structural and electrical properties for a series of YBa2(Cu1-xCox)3O7-δ ceramics. The Co doped YBa2Cu3O7-δ are (Y...The work reported in this paper aims at a better understanding of the magnetic doping effects on the structural and electrical properties for a series of YBa2(Cu1-xCox)3O7-δ ceramics. The Co doped YBa2Cu3O7-δ are (YBCO) prepared by conventional solid state reaction method and characterized by X-ray diffraction (XRD) and scanning electron microscopy (SEM), differential thermal analysis (DTA) and resistivity measurements. The crystal lattice parameters are found to change due to the cobalt doping and tendency to a structure phase transition from orthorhombic to tetragonal, which is confirmed by the decrease of the degree of orthorhombicity. The morphology examination with SEM revealed gradual increases of grain size with x = 0.02 Co, a high porosity is observed in the doped samples compared to the pure one. The decomposition temperature of YBCO is pushed from temperatures above 975°C to lower temperatures of 945°C. The resistivity measurements of doped samples with x = 0.04 and 0.06;shows a deviation in from T-linear behavior due to the opening of a pseudogap.展开更多
Cadmium sulfide（Cd S） thin films have been prepared by a simple technique such as chemical bath deposition（CBD）. A set of samples Cd S were deposited on glass substrates by varying the bath temperature from 55 to ...Cadmium sulfide（Cd S） thin films have been prepared by a simple technique such as chemical bath deposition（CBD）. A set of samples Cd S were deposited on glass substrates by varying the bath temperature from 55 to 75 °C at fixed deposition time（25 min） in order to investigate the effect of deposition temperature on Cd S films physical properties. The determination of growth activation energy suggests that at low temperature Cd S film growth is governed by the release of Cd^（2＋） ions in the solution. The structural characterization indicated that the Cd S films structure is cubic or hexagonal with preferential orientation along the direction（111） or（002）, respectively. The optical characterization indicated that the films have a fairly high transparency, which varies between55% and 80% in the visible range of the optical spectrum, the refractive index varies from 1.85 to 2.5 and the optical gap value of which can reach 2.2 e V. It can be suggested that these properties make these films perfectly suitable for their use as window film in thin films based solar cells.展开更多
文摘Polycrystalline zinc oxide (ZnO) thin films have been deposited at 450°C onto glass and silicon substrates by pulsed laser deposition technique (PLD). The used source was a KrF excimer laser (248 nm, 25 ns, 5 Hz, 2 J/cm2). The effects of glass and silicon substrates on structural and optical properties of ZnO films have been investigated. X-ray diffraction patterns showed that ZnO films are polycrystalline with a hexagonal wurtzite—type structure with a strong (103) orientation and have a good crystallinity on monocrystalline Si(100) substrate. The thickness and compositional depth profile were studied by Rutherford Backscattering spectrometry (RBS). The average transmittance of ZnO films deposited on glass substrate in the visible range is 70%.
文摘Cu(In, Al)Se2 thin films were prepared by electrodeposition from the aqueous solution consisting of CuCl2, InCl3, AlCl3 and SeO2 onto ITO coated glass substrates. The as-deposited films were annealed under vacuum for 30 min at temperature ranging between 200°C and 400°C. The structural, composition, morphology, optical band gap and electrical resistivity of elaborated thin films were studied, respectively using x-ray diffraction, energy dispersive analysis of x-ray, scanning electron microscopy, UV spectrophotometer and four-point probe method. The lattice constant and structural parameters viz. crystallite size, dislocation density and strain of the films were also calculated. After vacuum annealing, x-ray diffraction results revealed that all films were polycrystalline in nature and exhibit chalcopyrite structure with (112) as preferred orientation. The film annealed at 350°C showed the coexistence of CIASe and InSe phases. The average crystallite size increases linearly with annealing temperature, reaching a maximum value for 350°C. The films show a direct allowed band gap which increases from 1.59 to 1.78 eV with annealing temperature. We have also found that the electrical resistivity of films is controlled by the carrier concentration rather than by their mobility.
文摘The work reported in this paper aims at a better understanding of the magnetic doping effects on the structural and electrical properties for a series of YBa2(Cu1-xCox)3O7-δ ceramics. The Co doped YBa2Cu3O7-δ are (YBCO) prepared by conventional solid state reaction method and characterized by X-ray diffraction (XRD) and scanning electron microscopy (SEM), differential thermal analysis (DTA) and resistivity measurements. The crystal lattice parameters are found to change due to the cobalt doping and tendency to a structure phase transition from orthorhombic to tetragonal, which is confirmed by the decrease of the degree of orthorhombicity. The morphology examination with SEM revealed gradual increases of grain size with x = 0.02 Co, a high porosity is observed in the doped samples compared to the pure one. The decomposition temperature of YBCO is pushed from temperatures above 975°C to lower temperatures of 945°C. The resistivity measurements of doped samples with x = 0.04 and 0.06;shows a deviation in from T-linear behavior due to the opening of a pseudogap.
文摘Cadmium sulfide（Cd S） thin films have been prepared by a simple technique such as chemical bath deposition（CBD）. A set of samples Cd S were deposited on glass substrates by varying the bath temperature from 55 to 75 °C at fixed deposition time（25 min） in order to investigate the effect of deposition temperature on Cd S films physical properties. The determination of growth activation energy suggests that at low temperature Cd S film growth is governed by the release of Cd^（2＋） ions in the solution. The structural characterization indicated that the Cd S films structure is cubic or hexagonal with preferential orientation along the direction（111） or（002）, respectively. The optical characterization indicated that the films have a fairly high transparency, which varies between55% and 80% in the visible range of the optical spectrum, the refractive index varies from 1.85 to 2.5 and the optical gap value of which can reach 2.2 e V. It can be suggested that these properties make these films perfectly suitable for their use as window film in thin films based solar cells.
