Lijian Meng

Abstract: The TiO2 nanorod arrays, with about 1.8 mu m lengths, have been deposited on ITO substrates by dc reactive magnetron sputtering at different target-substrate distances. The average diameter of these nanorods can be modified from about 45 to 85 nm by adjusting the target-substrate distance from 90 to 50 mm. These nanorods are highly ordered and perpendicular to the substrate. Both XRD and Raman measurements show that the nanorods prepared at different target-substrate distances have only an anatase TiO2 phase. The nanorods prepared at the target-substrate distance less than 80 mm have a preferred orientation along the (2 2 0) direction. However, this preferred orientation disappears as the target-substrate distance is more than 80 mm. These TiO2 nanorods have been used as the electrodes for dye-sensitized solar cells (DSSCs). The highest conversion efficiency, about 4.78%, has been achieved for TiO2 nanorods prepared at 80 mm target-substrate distance. (C) 2010 Elsevier B.V. All rights reserved.

Abstract: Indium tin oxide (ITO) thin films have been deposited onto acrylics (PMMA) substrates by ion beam assisted deposition technique at different oxygen flows. The structural, optical and electrical properties of the deposited films have been characterized by X-ray diffraction, transmittance, FTIR, ellipsometry and Hall effect measurements. The optical constants of the deposited films have been calculated by fitting the ellipsometric spectra. The effects of the oxygen flow on the properties of the deposited films have been studied. It has been found that 40 sccm oxygen flow is an optimum value for getting the films with good transmittance and low electrical resistivity.

Abstract: A series of ZnO thin films doped with various vanadium concentrations were prepared on glass substrates by direct current reactive magnetron sputtering. The results of the X-ray diffraction (XRD) show that the films with doping concentration less than 10 at.% have a wurtzite structure and grow mainly along the c-axis orientation. The residual stress, estimated by fitting the XRD diffraction peaks, increases with the doping concentration and the grain size also has been calculated from the XRD results, decreases with increasing the doping concentration. The surface morphology of the ZnO:V thin films was examined by SEM. The optical constants (refractive index and extinction coefficient) and the film thickness have been obtained by fitting the transmittance. The optical band gap changed from 3.12 eV to 3.60 eV as doping concentration increased from 1.8 at.% to 13 at.% mol. All the results have been discussed in relation with doping concentration. (C) 2008 Elsevier B.V. All rights reserved.

Abstract: ZnO films doped with different vanadium concentrations are deposited onto glass substrates by dc reactive magnetron sputtering using a zinc target doped with vanadium. The vanadium concentrations are examined by energy dispersive spectroscopy (EDS) and the charge state of vanadium in ZnO thin films is characterized by x-ray photoelectron spectroscopy. The results of x-ray diffraction (XRD) show that all the films have a wurtzite structure and grow mainly in the c-axis orientation. The grain size and residual stress in the deposited films are estimated by fitting the XRD results. The optical properties of the films are studied by measuring the transmittance. The optical constants (refractive index and extinction coefficient) and the film thickness are obtained by fitting the transmittance. All the results are discussed in relation with the doping of the vanadium.

Abstract: Transparent conductive oxides (TCOs) such as indium tin oxide (ITO) thin films onto glass substrates are widely used as transparent and conductive electrodes for a variety of technological applications including flat panel displays, solar cells, smart windows, touch screens, etc. ITO films on glass and polycarbonate (PC) substrates were prepared at room temperature (RT) and at different P-O2. The films were characterized in terms of the surface roughness (delta), sheet resistance, the refractive index (n) and extinction coefficient (k). The free carrier density (n(c)) and the carrier mobility (mu) of the ITO (In2O3:Sn) films were measured and studied. The n(c) and mu values vary in different ratio of oxygen partial pressure (P-O2) of ITO deposition. The observed changes in the ITO film resistivity are due to the combined effect of different parameter values for n(c) and mu. From AFM analysis and spectra calculations, the surface roughness values of the ITO films were studied and it was observed that the delta values were lower than 15 nm. The energy band gap E-g ranges from 3.26 eV to 3.66 eV as determined from the absorption spectrum. It was observed an increase on the energy band gap as the P-O2 decrease in the range of 20-2% P-O2. The Lorentz oscillator classical model has also been used to fit the ellipsometric spectra in order to obtain both refractive index n and extinction coefficient k Values. (C) 2008 Elsevier Ltd. All rights reserved.

Abstract: Indium tin oxide (IT) films have been deposited onto glass substrates at room temperature by ion beam assisted deposition technique (IBAD) at different ion beam currents (80-120 mA). The effect of the ion beam current on films properties has been studied. The films prepared at low ion beam current (80 mA) show an almost amorphous structure. As the ion beam current is increased, films show a preferred orientation along the (222) direction. AFM measurements show that the surface RMS roughness of the film increases as the current goes up. The optical properties have been studied by measuring the transmittance. It has been found that the film prepared at 100 mA current has the highest transmittance. The optical constants of the films have been calculated by fitting the transmittance. The Hall measurements also showed that the film prepared at 100 mA current has one of the lowere electrical resistivities. FTIR measurements show that the film prepared at 100 mA current has the highest infra-red reflectance. All the measurements show the 100 mA ion beam current can produce good quality ITO films. (c) 2008 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Abstract: A transparent vanadium oxide film has been one of the most studied electrochromic (EC) and Thermochromic (TC) materials. Vanadium oxide films were deposited at different substrate temperatures up to 400 degrees C and different ratios of the oxygen partial pressure (P-O2). SEM, AFM and X-ray diffiraction's results show detail structure data of the films. IR mode assignments of the films measured by IR reflection-absorbance in NGIA, (near grazing incidence angle) are given. It is found that the film has V2O5 and VO2 combined structures. The films exhibit clear changes in transmittance when the environment temperature (T-e) is varied, especially in the 3600-4000 cm(-1) range. Applying a T-e that is higher than a critical temperature (T-c) to the samples, the as-RT (room temperature) deposited film with 9% P-O2 has a transmittance variation of 30%, but the films that were deposited on a heated substrate of 400 degrees C have little variation. There is tendency of bigger variation in transmittance for the sample deposited at a larger P-O2, when it is applied by 200 degrees C T-e. (C) 2007 Elsevier B.V. All rights reserved.

Abstract: Indium tin oxide (ITO) thin films have been deposited onto polycarbonate substrates by ion beam assisted deposition technique at room temperature. The structural, optical and electrical properties of the films have been characterized by X-ray diffraction, atomic force microscopy, optical transmittance, ellipsometric and Hall effect measurements. The effect of the ion beam energy on the properties of the films has been studied. The optical parameters have been obtained by fitting the ellipsometric spectra. It has been found that high quality ITO film (low electrical resistivity and high optical transmittance) can be obtained at low ion beam energy. In addition, the ITO film prepared at low ion beam energy gives a high reflectance in IR region that is useful for some electromagnetic wave shielding applications. (c) 2007 Elsevier B.V. All rights reserved.

Abstract: ITO films were deposited onto glass substrates by ion beam assisted deposition method. The oxygen ions were produced using a Kaufman ion source. The oxygen flow was varied from 20 until 60 sccm and the effect of the oxygen flow on properties of ITO films has been studied. The structural properties of the film were characterized by X-ray diffraction and atomic force microscopy. The optical properties were characterized by optical transmission measurements and the optical constants (refractive index n and extinction coefficient k) and film thickness have been obtained by fitting the transmittance using a semi-quantum model. The electrical properties were characterized by Hall effect measurements. It has been found that the ITO film with low electrical resistivity and high transmittance can be obtained with 40 sccm oxygen flow (the working pressure is about 2.3 x 10(-2) Pa at this oxygen flow). (c) 2007 Elsevier B.V. All rights reserved.

Abstract: We analyze the effect of the laser annealing on the crystallization of Er3+ doped amorphous Al2O3 thin films deposited on the silica-on-silicon substrate. These thin films were prepared by the microwave electron cyclotron resonance plasma source and were annealed by pulse CO2 laser. The Gauss intensity distribution of laser beam was mended at 3 x f position in the collimation system. Strong crystallization occurred in Al2O3 thin films and liquid phase crystallization was proposed to appear with the increase of laser powers. Photoluminescence intensity enhancement by a factor of 47 around 1.53 mu m has been realized by laser annealing process and Raman spectra study has suggested that Er3+ emission centers excited by Si nanocrystal (Si-nc) were formed in the Al2O3-SiO2 materials. The dual wavelength energy transfer mechanism between 800 nm and 980 nm is proposed in Er-doped Si-nc in Al2O3-SiO2 thin films. (c) 2006 Elsevier B.V. All rights reserved.

Abstract: TiO2 thin films were deposited on the glass substrates by dc reactive magnetron sputtering technique at different sputtering pressures (2 x 10(-3) to 2 x 10(-2) mbar). The films prepared at low pressures have an anatase phase, and the films prepared at high pressures have an amorphous phase. The optical properties were studied by measuring the transmittance and the ellipsometric spectra. The optical constants of the films in the visible range were obtained by fitting the transmittance combined with the ellipsometry measurements using the classical model with one oscillator. The refractive index of the films decreases from 2.5 until 2.1 as the sputtering pressure increases from 2 x 10(-3) to 2 x 10(-2) mbar. The films prepared at the pressure higher than 6 x 10(-3) mbar show a volume inhomogeneity. This volume inhomogeneity has been calculated by fitting the transmittance and the ellipsometric spectra. The volume inhomogeneity of the film prepared at the highest sputtering pressure is about 10%. Although the films prepared at high pressures show a large volume inhomogeneity, they have low extinction coefficients. It is suggested that the anatase phase results in more light scattering than amorphous phase does, and then a high extinction coefficient. (c) 2005 Elsevier B.V. All rights reserved.

Abstract: Vanadium pentoxide films were deposited onto glass substrates at different substrate temperatures (RT - 400 degrees C) by d.c. reactive magnetron sputtering. The structural properties of the films were studied by X-ray diffraction, scanning electron microscopy and Raman spectra. The optical properties of the films were studied by measuring and fitting the transmittance. The film prepared at low temperature showed a high optical transmittance. The film prepared at the substrate temperature lower than 200 degrees C has an amorphous structure and the film prepared at substrate temperatures higher than 200 degrees C had a polycrystalline V2O5 structure. The optical parameters of the films were calculated by fitting the transmittance using the classical model. (c) 2005 Elsevier B.V. All rights reserved.

Abstract: Three mixtures of poly(N-vinylcarbozole) (PVK) doped with 3, 1.5 and 0.1 wt% poly [2-methoxy 5-(2-ethylhexyloxy)-p-phenylene vinylene] (MEHPPV) are prepared. The phase-separation in these mixtures has been observed with atomic force microscopy (AFM) and demonstrated by photoluminescence (PL). The transient electroluminescence (EL) of PVK and MEHPPV in mixed PVK polymer light-emitting diodes (PLEDs) has been measured. The onset of PVK EL driven by electric pulse lagged behind that of MEHPPV in the mixture with 1.5, and 3 wt% dopant. But the EL onsets of MEHPPV and that of PVK in the mixture with 0.1 wt% dopant are the same. Moreover, the lag of EL onset of PVK behind that of MEHPPV increases with increasing doping concentration. The results demonstrate that the resultant carrier mobility of different phases of mixed polymers with low concentration dopant might be differentiated by means of transient EL. (c) 2005 Elsevier B.V. All rights reserved.

Abstract: Thermo-luminescence (TL) is a kind of luminescence decay measured with varying temperature. In the process of TL the decay parameter itself involves the temperature effect of traps. Thus the trap depth is inseparable from the decay parameter. There are two separate peaks in the TL curve of ZnS: Cu, Co if the measurement starts from liquid nitrogen temperature. In the experiment we started from zero Celsius temperature to isolate the deeper traps. We have proposed and realized three methods for simultaneous determination of trap depth and decay parameter based on the quasi-equilibrium model and experimental data. If we treat the case of kinetic order alpha = 1 as alpha = 2, the error might be as large as 100%.

Abstract: The acceleration ability of electrons in SiO2 and ZnS was compared through the variation of emission intensity based on ZnS : Er electroluminescence during the reverse of polarity of sinusoidal voltage. In order to avoid the influence of work function of electrode, cathodal and anodal materials were ITO (indium tin oxide). The ratio of maximum emission intensity under positive and negative half period is 2.18. This result demonstrates that the electron acceleration ability of SiO2 is 2.18 times stronger than that of ZnS.

Abstract: Vanadium-doped zinc oxide thin films with preferred c-axis orientation were deposited on glass substrates by DC-reactive co-sputtering. The deposited films were characterized by SEM, EDS, XRD and optical transmittance spectrum. The effect of V doping on the structural and optical proper-ties of ZnO thin films was studied. It is found that the sample has a highly c-axis orientation and a comparatively good crystallization with lower mass percentage of vanadium doping. All the V-dopped ZnO thin films are in compressive stress condition and compression stress increases as vanadium content is increased. Refractive index n is lowered firstly and then increased, while extinction coefficient k has a trend of rising, and optical band gap rises a little bit firstly and then diminishes obviously when vanadium content is increased.

Abstract: Silicon dioxide (SiO2) plays an important role in layered optimization scheme and solid-state cathodoluminescence (SSCL). Initially, it was believed that the SiO2 layer would (i) generate extra interface states contributing to a number of primary electrons available for exciting the luminescent centers, and/or (ii) act as acceleration layer resulted in gaining high energy for those electrons that would tunnel into the luminescent layer to excite luminescent centers. Based on the brightness vs. voltage (B-V) measurements, we deem that the latter case, i.e. acceleration and tunneling, is the dominant mechanism. A detailed discussion in terms of electrons acceleration and tunneling as the main contributions to the enhancement of brightness is presented. (c) 2005 Elsevier B.V. All rights reserved.

Abstract: Absorption is the underlying reason for the change in luminescence traits. And the lifetime influences the absorption in turn. This is a common law not only suitable for photoluminescence but also for other types of luminescence. In field emission display, two kinds of luminescence center have dramatically dissimilar lifetimes, which are co-doped in the same material. The spectrum changes with excitation frequency. Tuning color comes into reality in the same materials. The experiment proves that this law has something to do with lifetime, but has nothing to do with the way of excitation and the reasons for abruptly quenching.

Abstract: In layered optimization scheme and solid state cathodoluminescence, silicon oxidation plays a very important role in terms of hot electrons of obtaining high energy. The acceleration ability of electrons in SiO2 and ZnS were compared through the variation of emission intensity based on ZnS:Er phosphor during the reverse of polarity of sinusoidal voltage. The ratio of maximum emission intensity under positive and negative half period is 2.18. This result may be also demonstrated an important phenomenon: electrons were accelerated to a high energy by using secondary properties (acceleration of electrons) in SiO2 or ZnS. (c) 2005 Elsevier B.V. All rights reserved.

Abstract: The recombination luminescence is in nature a bimolecular process, but the decay rule may be changing from that of mono-molecular to bimolecular rule, i.e., from exponential to hyperbolic rule, depending on the behavior of conduction electrons. This behavior is represented by relative rate of recombination with ionized centers to that of capture by traps. This relative rate depends partly on the intrinsic parameters of the specified materials, and partly on the concentration of conduction electrons supplied by traps. Each point of the TL curve is related to the material parameters and the release of electrons from traps. The ratio of relative rate of recombination to that of capture gamma(epsilon) = [sigma(0)n(0)/sigma(v-n)] involves the parameter epsilon. They are inseparable and must be determined at the same time. In the present report, starting from the same sample ZnS: Cu, Co which has only one peak in its TL(i.e., only one kind of luminescent center and only one kind of traps), and the experimental value of sigma/sigma(0) = 0.005, the authors use thermo-luminescence kinetics models and some mathematic tools to exactly estimate the ratio [sigma(0)n(0)/sigma v] and the trap depth E simultaneously from the glow curve. The authors found that [sigma(0)n(0)/sigma v] = 2.6 and epsilon = 0.86 eV.

Abstract: In organic electroluminescence there is a sharp contradiction between the applicability of band model and molecular theory. This contradiction arose from the very beginning of extended study. In this report we studied the blue spectral shift in the newly discovered solid state cathodoluminescence when the applied voltage is increased. There are three different kinds of spectra in three intervals of applied voltage. The reason of this spectral shift is found to be the field ionization of exciton. The switching on of recombination starts only after the beginning of this field ionization. The exciton emission obeys molecular theory and the recombination obeys band model. Thus the demarcation is the appearance of field ionization of excitons. Since the ionization changes with electric field continuously, there is a region of coexistence of these two processes. (C) 2005 American Institute of Physics.

Abstract: The mainly characteristic of trapping materials is the trap depth. So it is significant to calculate the trap depth for the trapping materials. A new method of calculating trap depth, which is based on energy band and using rate equations to analyze thermoluminescence, was brought forward. This method which uses the rate equations of the process and the thermoluminescence curve can replace traditional methods such as first order or second order kinetics. The trap depth of SrAl2O4:Eu2+, Dy3+ and Sr4Al14O25:Eu2+, Dy3+ was estimated from the glow curve. Then the numevical solution of the trap depth can be obtained. From the results of experiments and calculations, this method can accurately indicate the whole process.

Abstract: Multilayer films based on tungsten oxide (WO3), ITO (indium tin oxide) and CdS were deposited mainly by reactive dc magnetron sputtering onto glass substrates for electrochromic application. The thin films were analyzed by means of XPS (X-ray photoelectron spectroscopy), GIXD (grazing incidence X-ray diffraction) and XRD (X-ray diffraction). XRD and XPS results confirmed that the films were WO3, CdS and ITO, respectively. The surface and interface of the CdS/ITO bi-layered film was studied by GIXD in different incidence angles. Detailed results about the amorphous characterization of the films during room temperature growth and post annealing are given.

Abstract: A bilayer CdS/ITO film was obtained. The dipped CdS was grown by an ultrasonic colloid deposition (USCD) method. Microstructure of the CdS film made by USCD has a wider transmission range and a higher transmittance. Amorphous indium-tin-oxide (ITO) thin film was deposited using d.c. magnetron-sputtering at room temperature. The ITO films exhibited good conductivity and maximum transmittance of 94%. The CdS/ITO bilayer was investigated by means of GIXD (grazing incidence X-ray diffraction) at different incidence angles (alpha = 0.20-5.00degrees) and XRD. We discuss a model for the thin bilayer film. SEM and AFM show that homogeneous CdS films with a bar-shaped ultrafine particles and ITO film with nanometer structure. The mechanism of the bilayer CdS/ITO film is discussed. (C) 2003 Elsevier Science B.V. All rights reserved.

Abstract: Indium-tin oxide (ITO) thin films were deposited on glass substrates at two different oxygen partial pressures (3.8 X 10(-4) and 1.2 X 10(-3) mbar). After the deposition, these films were annealed for 30 min in air at 200 degreesC and 400 degreesC, respectively. The effect of these post-deposition treatments on the structural, electrical and optical properties of ITO thin films has been studied. It,has been found that annealing at 200 degreesC is suitable for improving the properties of these ITO films. (C) 2002 Elsevier Science B.V. All rights reserved.

Abstract: Ruthenium dioxide films have been prepared by reactive r.f. magnetron sputtering at different oxygen partial pressures, different total sputtering pressures and different substrate temperatures (RT-500 degreesC). Raman measurements have been done for all the films. The three major Raman features, namely the E-g, A(1g) and B-2g modes can be observed in these films. The films prepared at high oxygen partial pressure and low total pressure show weak A(1g) peak intensity. The films prepared at low temperature show high B-2g peak intensity. As the temperature is increased, the intensity of the E-g Raman peak increases. This indicates a variation of the structure. By fitting the Raman peak, it has been found that the peak position of the RuO2 films has a red shift compared to that of the single crystal RuO2. This peak shift may be related with the residual stress in the films. In this work, these phenomena have been discussed. (C) 2003 Elsevier B.V. All rights reserved.

Abstract: In the present work we present a study of ZrO2/Al2O3 multilayers prepared by DC reactive sputtering with different ZrO2 layer thicknesses. To test their thermal stability, the multilayers were annealed at high temperature. A possible reason for the tetragonal phase to be stabilised in the multilayers is discussed. X-ray diffraction and Raman spectroscopy have been used to characterise the structure and the residual stress of the multilayers. (C) 2002 Elsevier Science Ltd. All rights reserved.

Abstract: ITO thin films were deposited on the glass substrates by microwave-enhanced d.c. reactive magnetron sputtering technique at different oxygen partial pressures (3.8-11.7 X 10(-4) mbar). The structural, electrical and optical properties of the deposited films have been studied. The films prepared at low oxygen pressure show an amorphous compact structure and the films prepared at high oxygen pressure show a polycrystalline structure with a preferred orientation along the (222) direction. The electrical resistivity of the films increases as the oxygen partial pressure is increased. The optical properties were studied by measuring the transmittance and the ellipsometric spectra. The optical constants of the films in the telecommunication wavelengths (1500-1600 nm) were obtained by fitting the transmittance combined with spectroscopic ellipsometry measurement. (C) 2002 Elsevier Science B.V. All rights reserved.

Abstract: Indium-Tin-Oxide (ITO) thin films were deposited on glass substrates using DC magnetron reactive sputtering at different bias voltages and substrate temperatures. Some improvements were obtained on film properties, microstructure and other physical characteristics for different conditions. Amorphous and polycrystalline films can be obtained for various deposition conditions. The transmission, absorption, spectral and diffuse reflection of ITO films were measured in some ranges of UV-Vis-NIR. The refractive index (n), Energy band gap E-g and the surface roughness of the film were derived from the measured spectra data. The carrier density (n(c)) and the carrier mobility (mu) of the film micro conductive properties were discussed. The films exhibited suitable optical transmittance and conductivity for electrochromic applications. (C) 2002 Elsevier Science B.V. All rights reserved.

Abstract: Zirconium oxide (ZrO2) films have been prepared by rf reactive magnetron sputtering at different sputtering pressures. It is found that the monoclinic phase is the dominant phase in the films and there is a small fraction of tetragonal phase in the films prepared in the low pressure region. The influence of sputtering pressure on the microstructure. residual stress and optical properties of the films has been studied. The films have been characterised by X-ray diffraction (XRD), scanning electron microscopy (SEM). energy dispersive X-ray (EDX) and optical spectroscopy. (C) 2001 Elsevier Science B.V. All rights reserved.

Abstract: Ruthenium oxide films have been deposited onto glass substrates by rf reactive magnetron sputtering at different substrate temperatures using a metallic target. The substrate temperature is varied from room temperature until 500 degreesC. The deposited films have been characterized by X-ray diffraction and Raman scattering. From X-ray diffraction, it can be found that the film prepared at room temperature shows a random orientation. As the substrate temperature is increased, the films show a preferred orientation along the (101) direction. When the temperature is higher than 400 degreesC, the preferred orientation changes from the (101) to the (200) direction. By analysis of the results, it has been found that the distance between the crystal planes for the films is higher than that for the powder and the difference becomes smaller when the temperature is increased. That means all the films are subject to a compressive stress and have a stress relaxation as the temperature is increased. From the Raman spectra, it can be found that the Raman peak shifts to the low Raman wave number when the temperature is decreased. This shift can be related with the residual stress in the films. Therefore, the results from the X-ray diffraction and Raman scattering can be combined for calculating the stress in the films. In this work, we will show that some information about the stress can be obtained by analysis of the Raman spectra and the X-ray diffraction. In addition, we will also show that the effects of the stress and the O/Ru ratio on the Raman peak shift can be separated. (C) 2000 Elsevier Science S.A. All rights reserved.

Abstract: Zirconium oxide (ZrO2) films have been prepared by rf reactive magnetron sputtering at different O-2 concentrations in the mixture sputtering gases. The films have been characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), energy dispersive X-ray (EDX) and optical spectroscopies. The influence of O-2 concentration in the sputtering gases on the microstructure, residual stress and optical properties of the films has been studied. Also, the effect of loose packing structure caused by the high O-2 gas concentration on the deposition rate has been discussed. (C) 2000 Elsevier Science Ltd. All rights reserved.

Abstract: ZrO2 films have been prepared by RF reactive sputtering using different substrate-target distances and RF powers. The films have been characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), and optical spectroscopy. Both monoclinic and tetragonal phases have been found in the films. All the films show a random orientation. The crystallite size increases as the substrate-target distance decreases and the RF power increases. It has been found that the residual stress of the films is mainly caused by the intrinsic stress. Also, the influence of substrate-target distance and RF power on the optical properties of the films has been discussed. (C) 2000 Elsevier Science B.V. All rights reserved.

Abstract: ZrO2-Y2O3 films with different Y2O3 concentrations have been prepared by rf magnetron reactive sputtering. The films have been characterised by X-ray diffraction (XRD), scanning electron microscopy (SEM), energy dispersive X-ray (EDX), Raman spectroscopy and optical spectroscopy. The influence of Y2O3 concentration on the microstructure and the optical properties have been discussed. Both tetragonal and cubic symmetries with a preferred orientation along (200)(c,t) plane are found. The crystallite size increases with the increasing of Y2O3 concentration. It can be found that the refractive index and the extinction coefficient decrease with increasing of Y2O3 concentration. (C) 2000 Elsevier Science B.V. All rights reserved.

Abstract: Indium tin oxide (ITO) films were deposited onto glass substrates by radio frequency reactive magnetron sputtering. The distance between the target and the substrate were changed from 50 to 100 mm. X-ray diffraction shows that film prepared at the larger target-substrate distance has a strong orientation along the (440) direction, and as the distance decreases, the intensity of the (440) peak decreases and the intensity of the (222) peak increases. The electrical resistivity of the ITO films decreases as the target-substrate distance gets small. This variation could be related to the change of the orientation of the films, since the film which has a strong (222) peak intensity has a low electrical resistivity. The optical transmittance of the ITO films decreases and the optical band gap moves to the low energy direction, as the target-substrate distance decreases. All of these phenomena will be discussed in this work. (C) 2000 American Vacuum Society. [S0734-2101(00)05204-0].

Abstract: Ruthenium dioxide (RuO2) films have been prepared by rf reactive magnetron sputtering at different oxygen partial pressures and total sputtering pressures. The films have been characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD) and electrical conductivity. The films prepared at low oxygen partial pressure and total pressure show a strong preferred orientation along the (110) direction. As both pressures increase, the peak intensity decrease. All the films are subject to a compressive stress. As the total pressure is decreased and the oxygen partial pressure is increased, the stress increases. When the total pressure is lower than 6 X 10(-3) mbar and the oxygen partial pressure is higher than 1 X 10(-3) mbar, the films peeled off automatically from the substrate because of the high stress. The films prepared at high oxygen partial pressure and high total pressure have a rough surface and those prepared at low pressure show smooth surface. In this paper, these phenomena have been discussed. In addition, the electrical properties of the films are also discussed. (C) 1999 Elsevier Science B.V. All rights reserved.

Abstract: Indium tin oxide (ITO) films were deposited onto the glass substrates at different substrate temperatures (RT-500 degrees C) by rf reactive magnetron sputtering method. The structural, optical and electrical properties of ITO films have been characterized by X-ray diffraction, scanning electron microscopy, optical transmittance and reflectance, sheet resistance and electrical resistivity measurements. The films deposited at low substrate temperature have a very strong (222) diffraction peak which means a preferred orientation along the [111] direction. As the temperature is increased, the (400) diffraction peak intensity increases and results in a preferred orientation along [100] direction for the films prepared at 500 degrees C substrate temperature. The film prepared at 400 degrees C substrate temperature has the lowest electrical resistivity (about 3.7 X 10(-4) Ohm cm). (C) 1998 Elsevier Science S.A. All rights reserved.

Abstract: RuO2 films have been prepared by rf reactive magnetron sputtering at different substrate temperatures (RT-500 degrees C). The structural and electrical properties of these films have been studied. The film prepared at room temperature has a random orientation. As the substrate temperature is higher than 200 degrees C, the film shows a preferred orientation along the [101] direction. However, as the temperature is higher than 400 degrees C, the preferred orientation of the film changes from [101] to [200] direction. The grain size in the films shows a gradual increase as the temperature is increased. All the films are subject to a compressive stress and show a stress relaxation as the temperature is increased. The SEM pictures show that the film prepared at low temperature indicates a microcrystalline structure with very small size, and the films prepared at high temperatures result in polycrystalline structures of about 0.3 mu m size. The measurements of the film resistivity show that all the films, except that prepared at room temperature, have a metallic behavior and the grain boundary scattering dominates the electrical resistivity of the films.

Abstract: Titanium nitride films have been grown onto glass substrates by d.c. reactive magnetron sputtering from a titanium metallic target at different nitrogen partial pressures. The influence of the nitrogen pressure on structural, electrical and optical properties of TiN films was investigated by measuring their X-ray diffraction, scanning electron microscopy, optical reflectance and electrical resistivity. The films show the (111) preferred orientation, the (111) peak intensity decreases as the nitrogen partial pressure is increased. The films have columnar structure and the grain size both along the sample surface and normal to the sample surface increases as the nitrogen partial pressure is increased. The film resistivity has been related with the variation of the film structure. The film, which has high(111) diffraction peak intensity, has high resistivity.

Abstract: The influence of the oxygen partial pressure on the properties of indium tin oxide films deposited by rf reactive magnetron sputtering has been studied. The oxygen partial pressure was varied from 3.2 x 10(-4) to 1.0 x 10(-3) mbar. It has been found that the 4 x 10(-4) mbar of oxygen partial pressure is a critical point. When the oxygen partial pressure is lower than 4 x 10(-4) mbar, the deposition rate of the films is high; the films have low transmittance and electrical resistivity; the X-ray diffraction shows that the films have a random orientation and the images of the scanning electron microscopy show that the films surface are smooth without structure. When the pressure is higher than 4 x 10(-4) mbar, the deposition rate is low and does not change as the oxygen partial pressure is further increased; the transmittance and the electrical resistivity are both high; the films show the preferred orientation along the (440) direction; the films surface show a clear structure and as the pressure is increased further, the films become porous. Considering both the factor of transmittance and resistivity, the optimum oxygen partial pressure will be 3.6 x 10(-4) mbar. The films prepared at this pressure have 80% transmittance and 9 x 10(-4) Omega cm resistivity. (C) 1997 Elsevier Science B.V.

Abstract: A set of indium tin oxide (ITO) films has been prepared by r.f. reactive magnetron sputtering at different total sputtering pressures using an indium tin alloy target. The effect of the pressure on ITO films properties have been studied. The pressure is varied from 0.08 to 0.76 Pa. The deposition rate does not show a significant variation with the pressure. The preferred orientation of ITO films change from the [222] to the [440] direction as the pressure is increased from 0.08 to 0.76 Pa. All the films are subject to a compressive stress. The film that prepared at high pressure show a very rough surface. All the films show a high optical transmittance. The film that prepared at low pressure give a low electrical resistivity. The lowest electrical resistivity which we have obtained in this work is about 2 x 10(-3) Omega cm. (C) 1997 Elsevier Science S.A.

Abstract: ITO films have been deposited onto glass substrates by rf reactive magnetron sputtering using an InSn (90-10) alloy target. After the deposition, the films were annealed in air at 500 degrees C for 30, 60, 90 and 180 min respectively. The film structure varies as the annealing time is changed. The films electrical properties show a strong dependence on the film structure. Although all the films show a preferred orientation along the (400) direction, the film which has a high (222) diffraction peak intensity has a high carrier mobility and a low resistivity.

Abstract: Titanium nitride films were prepared on glass substrates by dc reactive magnetron sputtering from a titanium metal target in an Ar+N-2 mixed atmosphere. During deposition, the total pressure was varied from 2x10(-3) to 3x10(-2) mbar. The effects of the total pressure on the structural, optical and electrical properties of the films were studied using X-ray diffraction, scanning electron microscopy, reflectance spectra and resistivity measurements.

Abstract: Tin doped indium oxide (ITO) films were deposited on glass substrates by rf reactive magnetron sputtering using a metallic alloy target (In-Sn, 90-10). The post-deposition annealing has been done for ITO films in air and the effect of annealing temperature on the electrical, optical and structural properties of ITO films was studied. It has been found that the increase of the annealing temperature will improve the film electrical properties. The resistivity of as deposited film is about 1.3 x 10(-1) Omega*cm and decreases down to 6.9 x 10(-3) Omega*cm as the annealing temperature is increased up to 500 degrees C. In addition, the annealing will also increase the film surface roughness which can improve the efficiency of amorphous silicon solar cells by increasing the amount of light trapping.

Abstract: ZnO films have been deposited on the glass substrates by de reactive magnetron sputtering method at different oxygen partial pressures (5 x 10(-4) to 3 x 10(-3) mbar). The deposited films have been characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), optical transmittance and reflectance, respectively. XRD results show that all the films are oriented with the c-axis perpendicular to the substrate. As oxygen partial pressure is increased, the grain size and diffraction peak intensify decrease. SEM results show that the films have columnar structure and the average crystallite dimension in the direction perpendicular to the c-axis decreases as oxygen partial pressure is increased. The film transmittance increases as oxygen partial pressure is increased. By comparing the diffuse transmittance and reflectance spectra of the films it has been found that the light loss in the film is mainly due to Rayleigh type scattering and the scattering decrease as the oxygen partial pressure is increased.

Abstract: Tin oxide thin films have been deposited on glass substrates by the d.c. reactive magnetron sputtering method. The dependence of electrical, structural and optical properties of films on the substrate temperature was studied. The single-oscillator model was used to fit the dispersion of the refractive index with the wavelength. Rayleigh-type scattering was assumed for explaining the variation of the transmittance.

Abstract: ZnO thin films were deposited onto glass substrates by d.c. reactive magnetron sputtering from a metallic zinc target. QI systematic study has been made on the influence of sputtering pressure in the range from 0.2 Pa to 3 Pa on the film structural and optical properties. At low sputtering pressure (0.2-0.4 Pa), the film was inhomogeneous, non-stoichiometric and had low refractive index and an almost amorphous structure. At high sputtering pressure (0.6-0.8 Pa), the film was homogeneous, stoichiometric and had high refractive index and the crystallinity was improved. As the sputtering pressure was further increased (1-3 Pa), the homogeneity and the refractive index of the film had no clear variation, but the crystallinity of the film went down. As the sputtering pressure was increased from 0.2 Pa to 3 Pa, the transmittance of the film increased and the deposition rate of the film decreased.

Abstract: The properties of zinc oxide films prepared by dc reactive magnetron sputtering were studied over a range of the substrate temperatures (room temperature to 450-degrees-C). The dependence of the structure of the films on the substrate temperature was studied using scanning electron microscopy and X-ray diffraction. The films had a preferred orientation along the (002) crystal plane at room temperature (50-degrees-C), a random orientation at 200-300-degrees-C and again a preferred orientation along the (002) crystal plane at 350-450-degrees-C. The grain size increased as the substrate temperature was raised. In addition, the optical and electrical properties have also been investigated.

Abstract: Titanium oxide films were deposited on glass substrates by d.c. reactive magnetron sputtering at different oxygen partial pressures (3.4 x 10(-4) mbar to 3 x 10(-3) mbar) and total pressures (2 x 10(-3) mbar to 2 x 10(-2),mbar). Two resolved peaks in the Ols spectra of XPS were observed. These two peaks were attributed to the O-Ti bonding and the O-H bonding. The O-H bonding component increased as the oxygen partial pressure and total pressure were increased. The near IR transmittance measurements showed that all films had an absorption near 2:8 mu m, and the absorption increased as the total pressure and oxygen partial pressure were increased. These phenomena were related to the porosity of the film. The films prepared by d.c. reactive magnetron sputtering generally have a columnar structure with many pores. In air some of these pores are filled with water, and this results in the appearence of the O-H bonding component and the absorption around 2.8 mu m. The increase of the O-H bonding component and the absorption around 2.8 mu m indicates the increase of the film porosity.

Abstract: X-ray photoelectron spectroscopy (XPS) analysis was performed on ZnO films prepared on glass substrates by DC reactive magnetron sputtering at different substrate temperatures (room temperature to 450-degrees-C). In the 0 ls spectra two resolved peaks were observed. The lower energy peak, located at 530 eV, corresponds to O-Zn bonding, while the higher energy peak, located at 532 eV, could be assigned to OH(531.5 eV) and/or H2O(533 eV) species. As the substrate temperature is increased, the oxygen component located at higher energy decreases. This variation was correlated with the structural properties of the films. The films prepared by DC reactive magnetron sputtering generally have a columnar structure with many pores. In air some of these pores are filled with water and result in the appearance of a higher energy peak in the 0 ls spectra. The decrease of the oxygen component located at higher energy indicates the decrease of the porosity of the films. The results obtained by scanning electron microscopy measurements were in agreement with this conclusion.

Abstract: Tin oxide films have been prepared on glass substrates by dc reactive magnetron sputtering using a metallic tin target of 99.99% purity (100 x 100 x 2 mm3) in an argon and oxygen mixed atmosphere. The influence of the oxygen partial pressure and total pressure on the X-ray diffraction, transmittance, resistivity, optical band gap, refractive index, packing density and deposition rate have been investigated systematically. When oxygen partial pressure is lower than 4 x 10(-3) mbar, the films show an amorphous structure and are not transparent in the visible region but are transparent in the near IR region. When oxygen partial pressure is between 4 x 10(-3) mbar and 6 x 10(-3) mbar, the films show a good polycrystalline structure, a high transmittance in the visible and near IR regions and a high packing density. When oxygen partial pressure is higher than 6 x 10(-3) mbar, the film structure deteriorates and the film packing density decreases. At fixed oxygen partial pressure, the film prepared at low total pressure has better structure and higher packing density than that prepared at high total pressure.

Abstract: TiO2 films have been deposited on glass substrates (75 X 25 mm2) by DC reactive magnetron sputtering from a pure 99.6% titanium plate of 100 X 100 mm2. During the sputtering process, the oxygen partial and total pressure were 6 X 10(-4) and 8 x 10(-3) mbar, respectively. The substrate temperature varied from ambient to 500-degrees-C. The results of X-ray diffraction show that all films have a anatase crystal structure. The film deposited at ambient has a (101) preferred orientation. With an increase in the substrate temperature, the films tend towards a random orientation. When the substrate temperature is higher than 450-degrees-C, the film again has a preferred orientation. However, the preferred orientation is not (101) but (004). As the substrate temperature is varied, the optical properties (refractive index, optical band gap and extinction coefficient) of TiO2 films also change significantly.

Abstract: La1-xSrxMO3 (M = Mn, Co) cathode materials were prepared and deposited on yttria stabilized zirconia electrolyte samples by screen-printing and dc reactive magnetron sputtering. Good bonding and mechanical stability of screen-printed electrodes requires high firing temperature, which might cause formation of resistive reaction products. These reaction products are detrimental to the electrode performance. The use of sputter deposition avoids high firing temperature and prevents chemical reaction between the electrode and electrolyte materials. The performance of electrode layers was evaluated by dc polarization measurements. Sputter deposition usually leads to better electrode microstructures than those obtained by screen-printing.

Abstract: TiO(x) films are deposited on glass substrates (75 x 25 mm2) by d.c. reactive magnetron sputtering from a pure 99.6% Ti disk. During the sputtering process, oxygen partial pressure and total pressure are 6 x 10(-2) Pa and 8 x 10(-1) Pa respectively. The substrate temperature varied from ambient to 500-degrees-C. The results of X-ray diffraction show that all films have an anatase crystal structure. The film deposited at ambient temperature is textured with the (101) crystal direction normal to the substrate surface. With increase in the substrate temperature, the films tend to be randomly oriented. When the substrate temperature is above 450-degrees-C, the film again has a preferred orientation. However, the preferred orientation is not (101) but (004). With the variation in substrate temperature, the optical properties (refractive index, optical band gap and extinction coefficient) of TiO2 films also change strongly. In this paper, these effects of substrate temperature on the films' properties are discussed.

Abstract: Zinc oxide films have been deposited on glass substrates by dc reactive magnetron sputtering from a metal zinc target. Thin films obtained by this deposition method are strongly textured with c-axis, crystal direction (002), normal to the substrate surface. A detailed investigation has been made on the influence of oxygen partial pressure and sputtering current on the linear optical properties of ZnO thin films. By optimizing these two parameters ZnO coatings may have a refractive index n close to single crystal data.

Abstract: Titanium oxide thin films were deposited on glass substrates by the d.c. reactive magnetron sputtering method. The dependence or structural and optical properties of films, and film composition, on the sputtering pressure was studied. The results of the X-ray diffraction show that all films only have the anatase TiO2 phase. At lower sputtering pressure, the film has a preferred orientation along (101) direction. As the sputtering pressure increases, the intensity of the (101) diffraction line decreases gradually. When the sputtering pressure is higher than 2 x 10(-2) mbar. the film exhibits an almost amorphous structure. The results of scanning electron microscopy show that the film structure changes from more dense to more porous as the sputtering pressure increases from 2 x 10(-3) mbar to 2 x 10(-2) mbar. These structure variations result in the variations in the optical properties. As the sputtering pressure increases from 2 x 10(-3) mbar to 2 x 10(-2) mbar, the refractive index n and extinction coefficient k (at 500 nm) vary from 2.48 to 2.14 and from 4.06 x 10(-3) to 0.59 x 10(-3) respectively.

Abstract: Titanium oxide thin films were grown on glass substrates by DC reactive magnetron sputtering at various oxygen partial pressures. The films were characterized using X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM) and optical transmittance spectra. The effects of the oxygen partial pressure on the structural and optical properties of titanium oxide films were investigated.

Abstract: Vanadium doped ZnO films with the doping concentration of 0.8% were deposited onto glass substrates at different sputtering pressures by direct current (DC) reactive magnetron sputtering using a zinc target doped with vanadium. The effect of the sputtering pressures (5*10(-3)-3*10(-2) mbar) on the structural properties of the deposited films have been studied by X-ray diffraction (XRD), scanning electron microscopy (SEM) and Energy Dispersive Spectrometry (EDS). The results of XRD show that all the films have a wurtzite structure and grow mainly with the c-axis orientation. The residual stresses which have been estimated by fitting the XRD results decrease with increasing sputtering pressure. The optical properties of the films were studied by measuring the transmittance. The optical constants (refractive index and extinction coefficient) and the film thickness were obtained by fitting the transmittance. All the results are discussed in relation with the sputtering pressure and the doping of the vanadium.

Abstract: The refractive index (n), the extinction coefficient (kappa), dielectric constant epsilon, free carrier density (n(c)) and the carrier mobility (mu) of the ITO (Indium-Tin-Oxide) films with different deposition time (or thickness), oxygen partial pressure ratio (P-O2) and annealing temperature were measured and studied. The calculated optical parameter-extinction coefficient (kappa) was obtained from the diffuse reflectance spectra using "scattering model". The Lorentz oscillator classical model has also been used for fitting the ellipsometric spectra in order to obtain both n and K values. As comparing the Swanepoel method was used for the refractive index. Clearly the results of the "scattering model", Swanepoel method and Ellipsometric method agree in magnitude. The films prepared at different P-O2 show different behaviour of the refractive index and extinction coefficient. The electrical characteristic parameter n(c) and mu were compared and studied by experimental measurements and calculations using an equation that relates the dielectric function and photo-energy (Drude theory) by Mathematic-4.1 software. Both measured and calculated values coincide in magnitude.

Abstract: TiO2 thin films were deposited on the glass substrates by dc reactive magnetron sputtering technique at different sputtering pressures. The films prepared at low pressures have an anatase phase, and the films prepared at high pressures have an amorphous phase. The optical properties were studied by measuring the transmittance and the ellipsometric spectra. The optical constants of the films in the visible range were obtained by fitting the transmittance combined with the ellipsometry measurements using the classical model with one oscillator. The films prepared at the pressure higher than 6 x 10(-3) mbar show a volume inhomogeneity. This volume inhomogeneity has been calculated by fitting the transmittance and the ellipsometric spectra.

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Abstract: ITO thin films were deposited on the glass substrates by microwave-enhanced dc reactive magnetron sputtering technique at different oxygen partial pressures (3.8 - 11.7 X 10(-4) mbar). The optical properties were studied by measuring the transmittance and the ellipsometric spectra. The optical constants of the films in the telecommunication wavelengths (1500-1600nm) were obtained by fitting the transmittance combined with spectroscopic ellipsometry measurement.

Abstract: Ruthenium dioxide films have been prepared by rf reactive magnetron sputtering at different oxygen partial pressures and total sputtering pressures. The films have been characterized by scanning electron microscopy, X-ray diffraction and electrical conductivity. The films prepared at low oxygen partial pressure and total pressure show a strong preferred orientation along the [110] direction. As both pressures increased, the peak intensity decreases. All the films are subject to a compressive stress. As the total pressure is decreased and the oxygen partial pressure is increased, the stress increases. When the total pressure is lower than 6 x 10(-3) mbar and the oxygen partial pressure is higher than 1 x 10(-3) mbar, the films peeled off automatically from the substrate because of the high stress. The films prepared at high oxygen partial pressure and high total pressure have a rough surface and those prepared at low pressure show smooth surface. In this paper, these phenomena have been discussed. In addition, the electrical properties of the films are also discussed.

Abstract: Titanium dioxide films have been deposited onto glass substrates by de reactive magnetron sputtering at different sputtering pressures (2x10(-3) - 2x10(-2) mbar). The films have been characterized by measuring their Raman scattering and X-ray diffraction (XRD). The films stress have been calculated by analysing their Raman spectra and X-ray deffraction spectra. Two methods give similar results which films prepared at low sputtering pressure have high stress values.

Abstract: ITO films have been deposited onto glass substrates by rf reactive magnetron sputtering using In-Sn (90-10) alloy target. After the deposition, the films were annealed in air at 500 degrees C for 30, 60, 90 and 180 min respectively. The film structure varies as the annealing time is changed. The film electrical properties show a strongly dependence on the film structure. Although all the films show a preferred orientation along the (400) direction, the film which has high (222) diffraction peak intensity, has high carrier mobility and low resistivity.

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