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1.
In this study, the influence of post deposition annealing steps (PDA) on the electrical resistivity of evaporated titanium/platinum thin films on thermally oxidised silicon is investigated. Varying parameters are the impact of thermal loading with maximum temperatures up to TPDA = 700 °C and the platinum top layer thickness ranging from 24 nm to 105 nm. The titanium based adhesive film thickness is fixed to 10 nm. Up to post deposition annealing temperatures of TPDA = 450 °C, the film resistivity is linearly correlated with the reciprocal value of the platinum film thickness according to the size effect. Modifications in the intrinsic film stress strongly influence the electrical material parameter in this temperature regime. At TPDA > 600 °C, diffusion of titanium into the platinum top layer and its plastic deformation dominate the electrical behaviour, both causing an increase in film resistivity above average. 相似文献
2.
The effect of Nb addition on grain size segregation and intergranular coupling of ternary CoCrPt alloys prepared by annealing of crystalline samples and crystallization of the Nb-rich (more than 4.6 at.%) amorphous films is investigated. Mean surface roughness as a function of Nb addition decreased for Nb contents of up to 2.7 at.% and then increased. The size and distribution of magnetic clusters were significantly affected by Nb addition. Vacuum annealing of the ternary and quaternary films (2.7 at.% Nb) increased the coercivity of the films from 53.71 kA/m and 52.09 kA/m to about 61.14 kA/m and 105 kA/m, respectively. Film with 12.1 at.% Nb was also produced and then annealed at different times and temperatures. Increasing the temperature to 700 °C caused the recrystallization of the 12.1 at.% Nb amorphous film. The observed magnetic properties are discussed in terms of composition, crystallographic orientation of deposited layer and oxidation of elements during annealing. 相似文献
3.
Doping of AsSSe amorphous films by silver photo-dissolution leads to a decrease of the optical gap and to an increase of the refractive index in forming AgAsSSe films. The difference of the optical gap and refractive index between undoped and doped films has been found in case of Ag15As26S29Se30 film up to 0.37 eV and 0.26, respectively. Transreflectance in far infrared spectral region indicates formation of AgAsS2 and AgAsSe2 entities in Ag15As26S29Se30 film. Scanning probe microscopy, namely atomic force microscopy, atomic force acoustic microscopy (AFAM) and Kelvin probe force microscopy (KPFM) was used for studying AgAsSSe films. It was found that silver growth is rather three dimensional and it is reminiscent of the Stranski-Krastanov growth mode. Observed silver protuberances represent silver reservoirs responsible for a local increase of silver content. Hence, the silver growth mode enhances formation of nano/meso inhomogeneities of the surface and near surface density/stiffness, seen in AFAM, and in the surface electric potential, seen in KPFM. 相似文献
4.
Nanocomposite (Ti1−xFex)Cy films with different compositions have been deposited by dc magnetron sputtering at 450 °C. The sputtered films could dissolve as much as 20-30 at.% of Fe on the Ti sites which is far above the maximum solid solubility at equilibrium. The solubility was dependent on the carbon content and more carbon-rich films could dissolve more Fe without the formation of Fe-precipitates. The addition of Fe also reduced the grain size of the carbide particles. Upon annealing, α-Fe starts to precipitate and the amount and size of these precipitates can be controlled by the annealing procedure and from the total composition of the as-deposited films. Mechanical and tribological studies show that some compositions of the (Ti1−xFex)Cy films have very good wear-resistant properties. These results together with magnetization measurements suggest that Ti-Fe-C films can be used as a wear-resistant magnetic thin film material. 相似文献
5.
Nanosheets of nickel catalyzed tungsten oxide have been grown on Si (100) substrate by electron beam rapid thermal annealing (ERTA) process. The thin films of W and Ni were deposited in a conventional electron beam evaporation system under high vacuum conditions and then subjected to ERTA. Scanning electron microscopy and atomic force microscopy were used to study the systematic growth of the nanosheets. Nanosheets with a uniform thickness of 200 nm were obtained for the beam current of 9 mA with a voltage of 5 kV ERTA for 60 s. X-ray diffractograms indicate that the formation of multiple phases of nickel, nickel oxide and tungsten oxide with respect to the variation in the beam current. Vibrating sample magnetometer studies indicate that the magnetic properties of this system vary with the beam current. 相似文献
6.
Fumikazu Imai Kimio Kunimori Takaaki Manabe Toshiya Kumagai Hisakazu Nozoye 《Thin solid films》1997,310(1-2):184-193
We synthesized titanium oxide thin films on MgO(100) single-crystal substrates by two reactive deposition methods and compared the structures of the thin films formed by these methods. In one method (pulsed-molecular-beam deposition method), molecular oxygen is supplied to the substrates by using a pulsed-molecular-oxygen beam source and deposition of one unit layer of titanium and subsequent supply of molecular oxygen are repeatedly performed. In the other method (radical beam deposition method), atomic oxygen is irradiated to the substrates by using an atomic oxygen beam generated by the radical beam source and irradiation of the atomic oxygen and deposition of titanium are simultaneously performed. In the case of the pulsed-molecular-beam deposition method, the crystal structure was changed by increasing the number of oxygen pulses supplied from the beam source. We found that the crystal structure of titanium oxide depended on the composition ratio of O:Ti in the film. The maximum ratio of O:Ti attainable by this method was 1.85, and at this ratio, (100)-oriented pseudorutile was formed. In the case of the radical beam deposition method, (100)-oriented anatase was formed below the titanium deposition rate of 0.10 nm/s and pseudorutile (TiO2−δ) was formed above 0.15 nm/s. The pseudorutile structure synthesized on this experiment was very stable in air. We concluded that the crystal structure of the pseudorutile is a new crystal structure of titanium oxide. 相似文献
7.
The influence of deposition power, thickness and oxygen gas flow rate on electrical and optical properties of indium tin oxide (ITO) films deposited on flexible, transparent substrates, such as polycarbonate (PC) and metallocene cyclo-olefin copolymers (mCOC), at room temperature was studied. The ITO films were prepared by radio frequency magnetron sputtering with the target made by sintering a mixture of 90 wt.% of indium oxide (In2O3) and 10 wt.% of tin oxide (SnO2). The results show that (1) average transmission in the visible range (400-700 nm) was about 85%-90%, and (2) ITO films deposited on glass, PC and mCOC at 100 W without supplying additional oxygen gas had optimum resistivity of 6.35 × 10−4 Ω-cm, 5.86 × 10−4 Ω-cm and 6.72 × 10−4 Ω-cm, respectively. In terms of both electrical and optical properties of indium tin oxide films, the optimum thickness was observed to be 150-300 nm. 相似文献
8.
Hexathiophene occupies a place of relevance in the context of organic semiconductors employed as active layers in opto-electronic devices. The knowledge of the structure of this class of materials in the film-phase is crucial for understanding and tailoring the performances of these devices. Here, thin films of hexathiophene have been deposited on silica by organic molecular beam deposition under controlled growth conditions. The structure of these films has been investigated by transmission electron diffraction compelling evidences of the presence of a structure different from the bulk phase. 相似文献
9.
Titanium oxide thin films were deposited by radiofrequency reactive sputtering in Ar-O2 atmosphere on silicon (100) wafers and titanium alloy plates (Ti-6Al-4V). Thin films structural characterization was carried out by grazing incidence X-ray diffraction, atomic force microscopy, scanning and transmission electron microscopies. Chemical composition was checked by X-ray wavelength dispersive spectroscopy. Mechanical assessment was achieved by nano-indentation and nano-scratch measurements. The films deposited on silicon substrates are over-stoechiometric in oxygen, with an oxygen to titanium ratio of about 2.2. The growth of anatase and rutile phases was promoted by ranging the total and oxygen partial pressures between 0.17-1.47 Pa and 35-85%. The growth rate of films, determined by grazing incidence X-ray reflectivity, was ranging from 35 to 55 nm/h. The rutile single-phased films possess a hardness of about 2.5 times higher and a lower friction coefficient than the anatase films. The films which contain anatase possess a high surface root-mean-square roughness and a reduced elastic modulus of around 120 GPa close to reduced elastic moduli of hydroxyapatite bioceramic and titanium alloy. So the anatase film could be the best candidate as a titanium oxide intermediate layer between hydroxyapatite and titanium alloy in the field of biomedical implants. 相似文献
10.
Ibrahimkutty Shyjumon Manesh Gopinadhan Christiane A. Helm Boris M. Smirnov Rainer Hippler 《Thin solid films》2006,500(1-2):41-51
Titanium clusters of nanometer sizes are produced by magnetron sputtering with subsequent aggregation in an argon gas flow. The produced Ti clusters are directed and deposited on a silicon substrate. Deposited films are analyzed by X-ray photoelectron spectroscopy in order to obtain the chemical composition and by atomic force microscopy and X-ray reflection methods to obtain information about the film structure. Experiments were carried out at different temperatures of the walls of the magnetron chamber. The size and the flux of clusters from the magnetron chamber are obtained by the analysis of the substrate surface with deposited clusters. It is found that the cluster parameters strongly depend on the temperature of the magnetron chamber walls. Molecules of titanium oxides may be nuclei of condensation and accelerate the nucleation process. A theoretical analysis based on experimental results is presented. It allows us to describe various stages of cluster evolution from their formation up to the deposition on the substrate and provides estimations for parameters of the processes involving clusters. 相似文献
11.
铝阳极氧化膜纳米孔阵列的微细结构 总被引:6,自引:0,他引:6
用电化学阳极氧化法制备了纳米多孔铝阳极氧化膜(AAO模板).采用原子力显微镜(AFM)测试AAO膜,研究了纳米孔阵列的形成机制.结果表明,在AAO膜的表面,除存在六方形的纳米孔阵列外,在孔端还存在六个微小的隆起,相邻的隆起之间彼此相连,看上去酷似一朵盛开的梅花,花的中心就是六方形纳米孔.二维AFM图像显示,以往用扫描电镜表征的纳米孔阵列,实际上是一幅排列整齐、并呈周期性变化的梅花阵列图案.膜背面阻挡层的AFM二维图像表明,膜胞呈六方形,且排列高度有序.膜胞密度为4.3×109/cm2,与孔密度基本一致.阻挡层的三维照片显示,膜胞的底部存在半球状突起,也呈现出规整的阵列图案. 相似文献
12.
Nanocomposite tantalum carbide/amorphous hydrocarbon (TaC/a-C:H) thin film composition, structure, and mechanical properties depend on the direct current bias voltage (Vb) level applied to the substrate during reactive sputter deposition. A set of TaC/a-C:H films was deposited across the range Vb = 0 to − 300 V with all other deposition parameters held constant except substrate temperature, which was allowed to reach its steady state during the depositions. Effects of Vb on film composition and structure were explored, including TaC crystallite size and dispersion using X-ray diffraction and high resolution transmission electron microscopy. In addition, the dependency of stress and hardness on Vb was studied with an emphasis on relationships to a-C:H phase structure. 相似文献
13.
Neelam Kumari 《Materials Research Bulletin》2010,45(4):464-473
The optical properties of Bi2V1−xMnxO5.5−x {x = 0.05, 0.1, 0.15 and 0.2 at.%} thin films fabricated by pulsed laser deposition on platinized silicon substrates were studied in UV-visible spectral region (1.51-4.17 eV) using spectroscopic ellipsometry. The optical constants and thicknesses of these films have been obtained by fitting the ellipsometric data (Ψ and Δ) using a multilayer four-phase model system and a relaxed Lorentz oscillator dispersion relation. The surface roughness and film thickness obtained by spectroscopic ellipsometry were found to be consistent with the results obtained by atomic force and scanning electron microscopy. The refractive index measured at 650 nm does not show any marginal increase with Mn content. Further, the extinction coefficient does not show much decrease with increasing Mn content. An increase in optical band gap energy from 2.52 to 2.77 eV with increasing Mn content from x = 0.05 to 0.15 was attributed to the increase in oxygen ion vacancy disorder. 相似文献
14.
Jianli Chen Xiaoming ZhangXianliang Zheng Chang LiuXiaoqiang Cui Weitao Zheng 《Materials Chemistry and Physics》2013
A convenient and efficient preparation method for separation graphene oxide with well-defined size distribution is developed using a centrifugation technique. The graded profile of graphene oxide nanosheets with narrow size distribution is effectively controlled by varying the centrifugation speed. The results show that the oxygen content of graphene oxide is highly dependent on their size distribution. Graphene oxide nanosheet with large size shows a red-shift in UV–vis absorption spectra, compared to graphene oxide with small size. This phenomenon is interpretation by a density functional theory calculation. The present work will provide a simple method to prepare graphene oxide nanosheets with controllable size distribution and C/O ratio, which will be valuable for the functionalization of graphene-based hybrids and the fabrication of graphene nano-devices. 相似文献
15.
Catalin Constantinescu Valentin IonAurelian C. Galca Maria Dinescu 《Thin solid films》2012,520(20):6393-6397
We present here results on samarium oxide thin films, obtained by pulsed laser deposition and by radio frequency assisted pulsed laser deposition. Three different substrate types were used: silicon, platinum covered silicon and titanium covered silicon. The influence of the deposition parameters (oxygen pressure and laser fluence) on the structure and morphology of the thin films was studied. The substrate-thin film interface zone was investigated; the optical and electrical properties (the losses, dielectric constant and leakage currents) were also determined. 相似文献
16.
V. Kapaklis P. Poulopoulos V. Karoutsos Th. Manouras C. Politis 《Thin solid films》2006,510(1-2):138-142
Thin Ag films in the thickness range D = 14–320 nm were deposited by radio frequency magnetron sputtering on glass substrates at room temperature inside a vacuum chamber with base pressure of about 5 × 10− 6 Pa. The growth of the films was studied via X-ray diffraction and atomic force microscopy experiments. The two techniques are complementary and give us the opportunity to study the surface roughness, the statistical distribution and the average value of the grain size, as well as the texture of the samples. It is shown that the film roughness increases negligibly within the first 60 atomic layers of growth. The thicker films (D 300 nm) develop a nanocrystalline structure with a root mean square roughness of about 2.5 nm. The grain size evolves linearly with the thickness from 9.4 nm at D = 54 nm to 31.6 nm at D = 320 nm. 相似文献
17.
P.G. Louie Frobel S.R. Suresh S. Mayadevi S. Sreeja Chandrachur Mukherjee C.I. Muneera 《Materials Chemistry and Physics》2011
Intense reverse saturable absorption is reported for the first time in solid films of a new organic–polymer nanocomposite, cast by doping Biebrich Scarlet dye in a vinyl polymer host polyvinyl alcohol for various concentrations, as studied employing the Z-scan technique at 442 nm under different peak incident intensities ranging from 9.37 × 102 to 104.18 × 102 W cm−2. The sample also exhibited nonlinear refraction under the experimental conditions. The estimated values of the effective coefficients of nonlinear absorption βeff(0.27 × 10−2 to 45.5 × 10−2 cm W−1) as well as nonlinear refraction n2 (−1.5 × 10−7 to −2.75 × 10−7 cm2 W−1) measured up to the highest reported ones for low power continuous wave excitation. The composite films were characterized as nanoclusters consisting of dye molecules encapsulated between larger molecules of the amorphous polymer and having a low average roughness (≈1 nm) for the surface. These results, together with the simple and flexible processing method for the dye–polymer composite, imply that BS–PVA composite films have promising optical properties as an efficient low threshold nanocomposite material for potential applications in nonlinear optical devices. 相似文献
18.
M. Harsha Vardhan Reddy Rusul M. Al-Shammari Nebras Al-Attar Luke Rogers Sergio Lopez Robert J. Forster Mathias O. Senge Tia E. Keyes James H. Rice 《Materials Chemistry and Physics》2014
Studied here are thin films of a series of phenyl-porphyrins. The effect of the phenyl number and positioning on the porphyrin core is shown to have a significant impact on the ability of phenyl-porphyrins to produce aggregates. When four phenyl groups (H2TPP) and three phenyl groups are present (H2-Tri-PP) a strong aggregate film forms with fractal like structure. When two phenyl groups are present little evidence for aggregation can be determined, however fractal structure persists. 相似文献
19.
An amorphous, 150 μm thick freestanding sheet of a TiAl-based alloy was produced by physical vapor deposition (PVD). The following phase transformations were observed after different stages of crystallization of the amorphous sheet and analyzed using differential thermal analysis, X-ray diffraction, and transmission electron microscopy: amorphous→body centered cubic (β)→hexagonal close-packed ()?→tetragonal (γ)+ordered 2. The β phase was formed as near-spherical particles that were evenly distributed in the amorphous phase and the size of these particles was approximately 90 nm. Formation of the phase by decomposition of β and the remaining amorphous phases led to a very fine feathery-like microstructure arranged in colonies of approximately 100 nm in size. Interface boundaries between the phase particles were poorly defined. The transformation of the metastable phase into a mixture of the γ and 2 phases led to formation of an equiaxed γ-grain structure with the grain size of approximately 150 nm. 相似文献
20.
Usha Parihar K. Sreenivas J.R. Ray C.J. Panchal N. Padha Bharati Rehani 《Materials Chemistry and Physics》2013
Chalcopyrite copper indium aluminum diselenide (CuIn0.81Al0.19Se2) compound is prepared by direct reaction of high purity elemental copper, indium, aluminum and selenium in their stoichiometric proportion. Structural and compositional characterizations of pulverized material confirm the formation of a single phase, polycrystalline nature. CuInAlSe2 (CIAS) thin films are deposited on organically cleaned soda lime glass substrates using flash evaporation technique by varying the substrate temperatures in the range from 423 K to 573 K. Influence of substrate temperature observed by X-ray diffraction (XRD), scanning electron microscope (SEM), optical and electrical measurement. CIAS Films grown at different substrate temperatures are polycrystalline in nature, exhibiting a chalcopyrite structure with lattice parameters a = ∼0.576 nm and c = ∼1.151 nm. The crystallinity in the films increases with increasing substrate temperature up to 473 K, and tend to degrade at higher substrate temperatures. Optical band gap is in the range of 1.20 eV–1.38 eV and the absorption coefficient is close to 105 cm−1. Electrical characterization reveals p-type conductivity and the structural, morphological and optical properties indicate potential use of CIAS thin films as an absorber layer for thin film solar cell applications. 相似文献