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1.
Bi5GexSe95−x (30, 35, 40 and 45 at.%) thin films of thickness 200 nm were prepared on glass substrates by the thermal evaporation technique. The influence of composition and annealing temperature, on the structural and electrical properties of Bi5GexSe95−x films was investigated systematically using X-ray diffraction (XRD), energy dispersive X-ray analysis (EDX). The XRD patterns showed that the as-prepared films were amorphous in nature with few tiny crystalline peaks of relatively low intensity for 30 and 45 at.% and the Bi5Ge40Se55 annealed film was polycrystalline. The chemical composition of the Bi5Ge30Se65 film has been checked using energy dispersive X-ray spectroscopy (EDX). The electrical conductivity was measured in the temperature range 300-430 K for the studied compositions. The effect of composition on the activation energy (ΔE) and the density of localized states at the Fermi level N(EF) were studied, moreover the electrical conductivity was found to increase with increasing the annealing temperature and the activation energy was found to decrease with increasing the annealing temperature. The results were discussed on the basis of amorphous-crystalline transformations. 相似文献
2.
S.C. Su Y.M. Lu Z.Z. Zhang D.Z. Shen J.Y. Zhang X.W. Fan 《Applied Surface Science》2008,254(15):4886-4890
The Zn1−xMgxO thin films were grown on Al2O3 substrate with various O2 flow rates by plasma-assisted molecular beam epitaxy (P-MBE). The growth conditions were optimized by the characterizations of morphology, structural and optical properties. The Mg content of the Zn1−xMgxO thin film increases monotonously with decreasing the oxygen flux. X-ray diffractometer (XRD) measurements show that all the thin films are preferred (0 0 2) orientated. By transmittance and absorption measurements, it was found that the band gap of the film decreases gradually with increasing oxygen flow rate. The surface morphology dependent on the oxygen flow rate was also studied by field emission scanning electron microscopy (FE-SEM). The surface roughness became significant with increasing oxygen flow rate, and the nanostructures were formed at the larger flow rate. The relationship between the morphology and the oxygen flow rate of Zn1−xMgxO films was discussed. 相似文献
3.
BiFeO3/Zn1−xMnxO (x = 0-0.08) bilayered thin films were deposited on the SrRuO3/Pt/TiO2/SiO2/Si(1 0 0) substrates by radio frequency sputtering. A highly (1 1 0) orientation was induced for BiFeO3/Zn1−xMnxO. BiFeO3/Zn1−xMnxO thin films demonstrate diode-like and resistive hysteresis behavior. A remanent polarization in the range of 2Pr ∼ 121.0-130.6 μC/cm2 was measured for BiFeO3/Zn1−xMnxO. BiFeO3/Zn1−xMnxO (x = 0.04) bilayer exhibits a highest Ms value of ∼15.2 emu/cm3, owing to the presence of the magnetic Zn0.96Mn0.04O layer with an enhanced Ms value. 相似文献
4.
S.D. Chavhan 《Applied Surface Science》2008,254(15):4539-4545
Herein is a report of a study on a Cd1−xZnxS thin film grown on an ITO substrate using a chemical bath deposition technique. The as-deposited films were annealed in air at 400 °C for 30 min. The composition, surface morphology and structural properties of the as-deposited and annealed Cd1−xZnxS thin films were studied using EDX, SEM and X-ray diffraction techniques. The annealed films have been observed to possess a crystalline nature with a hexagonal structure. The optical absorption spectra were recorded within the range of 350-800 nm. The band gap of the as-deposited thin films varied from 2.46 to 2.62 eV, whereas in the annealed film these varied from 2.42 to 2.59 eV. The decreased band gap of the films after annealing was due to the improved crystalline nature of the material. 相似文献
5.
H.T. Chen M.F. Yan 《Physica B: Condensed Matter》2012,407(8):1183-1185
We investigated the hardness enhancement in titanium carbonitrides (TiCxN1−x) by the population analysis method based on first-principles calculations. Populations for bonds TiC and TiN in TiCxN1−x (0.25<x<0.75) are all positive. The enhanced hardness for titanium carbonitrides is well explained by overlap population analysis. Intrinsic hardness of TiCxN1−x has been calculated based on the obtained overlap populations. The calculated results are in good agreement with the available experimental data. 相似文献
6.
Wenting Xu Hailing TuQinghua Xiao Qing ChangZongfeng Li Dali Liu 《Applied Surface Science》2011,257(22):9260-9263
The Si1−xGex thin layer is fabricated by two-step Ge ion implantation into (0 0 1) silicon. The embedded SiGe nanoclusters are produced in the Si1−xGex layer upon further annealing. The number and size of the nanoclusters changed due to the Ge diffusion during annealing. Micro defects around the nanoclusters are illustrated. It is revealed that the change of Si-Si phonon mode is causing by the nanoclusters and micro defects. 相似文献
7.
A series of ZnO1−xSx alloy films (0 ≤ x ≤ 1) were grown on quartz substrates by radio-frequency (rf) magnetron sputtering of ZnS ceramic target, using oxygen and argon as working gas. X-ray diffraction measurement shows that the ZnO1−xSx films have wurtzite structure with (0 0 2) preferential orientation in O-rich side (0 ≤ x ≤ 0.23) and zinc blende structure with (1 1 1) preferential orientation in S-rich side (0.77 ≤ x ≤ 1). However, when the S content is in the range of 0.23 < x < 0.77, the ZnO1−xSx film consists of two phases of wurtzite and zinc blende or amorphous ZnO1−xSx phase. The band gap energy of the films shows non-linear dependence on the S content, with an optical bowing parameter of about 2.9 eV. The photoluminescence (PL) measurement reveals that the PL spectrum of the wurtzite ZnO1−xSx is dominated by visible band and its PL intensity and intensity ratio of UV to visible band decrease greatly compared with undoped ZnO. All as-grown ZnO1−xSx films behave insulating, but show n-type conductivity for w-ZnO1−xSx and maintain insulating properties for β-ZnO1−xSx after annealed. Mechanisms of effects of S on optical and electrical properties of the ZnO1−xSx alloy are discussed in the present work. 相似文献
8.
The optical properties of CdxZn1−xS thin films on glass substrate prepared by spray pyrolysis method
A series of CdxZn1−xS thin films have been deposited on glass substrates using spray pyrolysis technique. The crystallinity and microstructure of CdxZn1−xS thin films have been investigated by X-ray diffraction (XRD). Based on the results of Hall measurements, the films obtained were an n-type semiconductor. The X-ray data analysis of CdxZn1−xS thin films showed that the grain size of the CdxZn1−xS increased with increase in Cd composition. It is observed that the band gap increases as the Cd composition decreases. The results also showed a blue shift of absorption edge of optical transmission spectra is increases as Zn ratio increases. The effects of Cd composition on the structural and optical properties of CdxZn1−xS thin films were related to their grain size, stress and carrier concentration. 相似文献
9.
Feihui Li 《Applied Surface Science》2009,255(7):4225-4231
The electrochemical behaviors of BiIII, TeIV and SbIII single ions and their mixtures were investigated in nitric acid and hydrochloric acid system separately. Based on which, BixSb2−xTey thermoelectric films were prepared by potentiostatic electrodeposition from the solutions with different concentrations of BiIII, TeIV and SbIII in the two acid systems. The morphologies, compositions, structures, Seebeck coefficients and resistivities of the deposited thin films were characterized and compared by ESEM (or FESEM), EDS, XRD, Seebeck coefficient measurement system and four-probe resistivity measuring device respectively. The results show that although BixSb2−xTey thermoelectric thin film which structure is consistent with the standard pattern of Bi0.5Sb1.5Te3 can be gained in both of the two acid solutions by adjusting the deposition potential, their morphologies and thermoelectric properties have big differences in different acid solutions. 相似文献
10.
Ternary polycrystalline Zn1−xCdxO semiconductor films with cadmium content x ranging from 0 to 0.23 were obtained on quartz substrate by pulse laser deposited (PLD) technique. X-ray diffraction measurement revealed that all the films were single phase of wurtzite structure grown on c-axis orientation with its c-axis lattice constant increasing as the Cd content x increasing. Atomic force microscopy observation revealed that the grain size of Zn1−xCdxO films decreases continuously as the Cd content x increases. Both photoluminescence and optical measurements showed that the band gap decreases from 3.27 to 2.78 eV with increasing the Cd content x. The increase in Cd content x also leads to the broadening of the emission peak. The resistivity of Zn1−xCdxO films decreases evidently for higher values of Cd content x. The shift of PL emission to visible light as well as the decrease of resistivity makes the Zn1−xCdxO films potential candidate for optoelectronic device. 相似文献
11.
M.M. El-Nahass M.A.M. Seyam H.E.A. El-Sayed A.M. Abd El-Barry 《Applied Surface Science》2006,252(18):6218-6227
Thin films of samples of the glassy SxSe100−x system with 0 ≤ x ≤ 7.28 have been prepared by thermal evaporation technique at room temperature (300 K). X-ray investigations show that the structure of pure selenium (Se) does change seriously by the addition of small amount of sulphur S ≤7.28%. The lattice parameters were determined as a function of sulphur content. Results of differential thermal analysis (DTA) of the glassy compositions of the system SxSe100−x were discussed. The characteristic temperatures (Tg, Tc and Tm) were evaluated. Dark electrical resistivities, ρ, of SxSe100−x thin films with different thicknesses from 100 to 500 nm, were measured in the temperature range from 300 to 423 K. Two distinct linear parts with different activation energies were observed. The variation of electrical resistivity of examined compositions has been discussed as a function of the film thickness, temperature and the sulphur content. The application of Mott model for the phonon assisted hopping of small polarons gave the same two activation energies obtained from the resistivity temperature calculations. 相似文献
12.
The effects of thermal annealing in vacuum on the bonding structures, optical and mechanical properties for germanium carbide (Ge1−xCx) thin films, deposited by radio frequency (RF) reactive sputtering of pure Ge(1 1 1) target in a CH4/Ar mixture discharge, are investigated. We find that there are no significant changes in the bonding structure of the films annealed below 300 °C. The fraction of Ge-H bonds for the film annealed at temperatures (Ta) above 300 °C decreases, whereas that of C-H bonds show a decrease only when Ta exceeds 400 °C. The out-diffusion of hydrogen promotes the formation of Ge-C bonds at Ta above 400 °C and thus leads to a substantial increase in the compressive stress and hardness for the film. The refractive indices and optical gaps for Ge1−xCx films are almost constant against Ta, which can be ascribed to the unchanged ratios of Ge/C and sp2-C/sp3-C concentrations. Furthermore, we also find that the excellent optical transmission for an antireflection Ge1−xCx double-layer film on ZnS substrate is still maintained after annealing at 700 °C. 相似文献
13.
The a-C:H and a-C:NX:H films were deposited onto silicon wafers using radio frequency (rf) plasma enhanced chemical vapor deposition (PECVD) and pulsed-dc glow discharge plasma CVD, respectively. Raman spectroscopy and X-ray photoelectron spectroscopy (XPS) were used to characterize chemical nature and bond types of the films. The results demonstrated that the a-C:H film prepared by rf-CVD (rf C:H) has lower ID/IG ratio, indicating smaller sp2 cluster size in an amorphous carbon matrix. The nitrogen concentrations of 2.9 at.% and 7.9 at.% correspond to carbon nitride films prepared with rf and pulse power, respectively.Electrochemical corrosion performances of the carbon films were investigated by potentiodynamic polarization test. The electrolyte used in this work was a 0.89% NaCl solution. The corrosion test showed that the rf C:H film exhibited excellent anti-corrosion performance with a corrosion rate of 2 nA cm−2, while the carbon nitride films prepared by rf technique and pulse technique showed a corrosion rate of 6 nA cm−2 and 235 nA cm−2, respectively. It is reasonable to conclude that the smaller sp2 cluster size of rf C:H film restrained the electron transfer velocity and then avoids detriment from the exchange of electrons. 相似文献
14.
Da-Yong Jiang Ke-Wei Liu Yan-Min Zhao Bin Yao De-Zhen Shen 《Applied Surface Science》2008,254(7):2146-2149
MgxZn1−xO alloy films were prepared on sapphire substrates using Ar and N2 as the sputtering gases. The effect of the sputtering gas on the structural, optical and electrical properties of the MgxZn1−xO films was studied. By using N2 as the sputtering gas, the MgxZn1−xO film shows p-type conductivity and the band gap is larger than that employing Ar as the sputtering gas. The reason for this phenomenon is thought to be related to the reaction between N-O or N-Zn, and the N-doping. 相似文献
15.
Y.M. Zhao J.Y. Zhang K.W. Liu C.X. Shan B. Yao B.H. Li D.Z. Shen 《Applied Surface Science》2007,253(24):9319-9322
We report the growth of cubic MgxZn1−xO alloy thin films on quartz by electron beam evaporation. It can be found that all the samples have sharp absorption edges by the absorption measurements. X-ray diffraction measurements indicate the MgxZn1−xO films are cubic phase with preferred orientation along the (1 1 1) direction. Energy dispersive spectrometry (EDS) demonstrates that the Mg concentration in MgxZn1−xO films is much higher than the ceramic target used, and the composition can be tuned in a small scope by varying the substrate temperature and the beam electric current. The reasons of this phenomenon are also discussed. 相似文献
16.
R.L. Hadimani P.A. BartlettY. Melikhov J.E. SnyderD.C. Jiles 《Journal of magnetism and magnetic materials》2011,323(5):532-534
Gd5(SixGe1−x)4, known for its giant magnetocaloric effect, also exhibits a colossal strain of the order of 10,000 ppm for a single crystal near its coupled first-order magnetic-structural phase transition, which occurs near room temperature for the compositions 0.41≤x≤0.575. Such colossal strain can be utilised for both magnetic sensor and actuator applications. In this study, various measurements have been carried out on strain as a function of magnetic field strength and as a function of temperature on single crystal Gd5Si2Ge2 (x=0.5), and polycrystalline Gd5Si1.95Ge2.05 (x=0.487) and Gd5Si2.09Ge1.91 (x=0.52). Additionally a giant magnetostriction/thermally induced strain of the order of 1800 ppm in polycrystalline Gd5Si2.09Ge1.91 was observed at its first order phase transition on varying temperature using a Peltier cell without the use of bulky equipment such as cryostat or superconducting magnet. 相似文献
17.
SiCxNy thin films with different nitrogen contents were deposited by way of incorporation of different amounts of nitrogen into SiC0.70 using unbalanced reactive dc magnetron sputtering method. Their phase configurations, nanostructures and mechanical behaviors were investigated by X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), Raman spectroscopy, high-resolution transmission electron microscopy (HRTEM) and microindentation methods. The result indicated SiC0.70 and all SiCxNy thin films exhibited amorphous irrespective of the nitrogen content. The phase configuration and mechanical behaviors of SiCxNy thin films strongly depended on nitrogen content. SiC0.70 exhibited a mixture consisting of SiC, Si and a small amount of C. Incorporated nitrogen, on one hand linked to Si, forming SiNx, on the other hand produced CNx and C at the expense of SiC. As a result, an amorphous mixture consisting of SiC, SiNx, C and CNx were produced. Such effects were enhanced with increase of nitrogen content. A low hardness of about 16.5 GPa was obtained at nitrogen-free SiC0.70. Incorporation of nitrogen or increase of nitrogen content increased the film hardness. A microhardness maximum of ∼29 GPa was obtained at a nitrogen content of 15.7 at.%. This value was decreased with further increase of N content, and finally a hardness value of ∼22 GPa was obtained at a N content of ∼25 at.%. The residual compressive stress was consistent with the hardness in the nitrogen content range of 8.6-25.3 at.%. 相似文献
18.
J.Q. Zhu C.Z. JiangJ.C. Han H.L. YuJ.Z. Wang Z.C. JiaR.R. Chen 《Applied Surface Science》2012,258(8):3877-3881
Amorphous non-hydrogenated germanium carbide (a-Ge1−xCx) films have been prepared by magnetron co-sputtering method in a discharge of Ar. The dependence of structural and chemical bonding properties on the Ge/C ratio (R) has been investigated by X-ray photoelectron spectroscopy, Fourier transform infrared spectroscopy and Raman spectroscopy. The relationship between the chemical bonding and the optical and electrical properties of the a-Ge1−xCx films has also been explored. It has been shown that the refractive index of the films increases from 2.9 to 4.4 and the optical gap decreases from 1.55 to 1.05 eV as R increases from 1.22 to 5.67. Moreover, the conductivity σ increases clearly and the activation energy Ea decreases with the increasing R owing to the reduction of sp3 CGe bonds. The a-Ge1−xCx films exhibit refractive index and optical gap values changing with x in a wide range, which may make a-Ge1−xCx films good candidates in the fields of protection coatings for IR windows and electronic devices. 相似文献
19.
Chen-Cheng Sun Shih-Chin Lee Yaw-Shyan Fu Yu-Hwe Lee 《Applied Surface Science》2006,252(23):8295-8300
CrNx thin films have attracted much attention for semiconductor IC packaging molding dies and forming tools due to their excellent hardness, thermal stability and non-sticking properties (low surface free energy). However, few data has been published on the surface free energy (SFE) of CrNx films at temperatures in the range 20-170 °C. In this study CrNx thin films with CrN, Cr(N), Cr2N (and mixture of these phases) were prepared using closed field unbalanced magnetron sputtering at a wide range of Cr+2 emission intensity. The contact angles of water, di-iodomethane and ethylene glycol on the coated surfaces were measured at temperatures in the range 20-170 °C using a Dataphysics OCA-20 contact angle analyzer. The surface free energy of the CrNx films and their components (e.g., dispersion, polar) were calculated using the Owens-Wendt geometric mean approach. The influences of CrNx film surface roughness and microstructure on the surface free energy were investigated by atomic force microscopy (AFM) and X-ray diffraction (XRD), respectively. The experimental results showed that the lowest total SFE was obtained corresponding to CrN at temperature in 20 °C. This is lower than that of Cr(N), Cr2N (and mixture of these phases). The total SFE, dispersive SFE and polar SFE of CrNx films decreased with increasing surface temperature. The film roughness has an obvious effect on the SFE and there is tendency for the SFE to increase with increasing film surface roughness. 相似文献
20.
A series of TiSixNy superhard coatings with different Si contents were prepared on M42 steel substrates using two Ti and two Si targets by reactive magnetron sputtering at 500 °C. These samples were subsequently vacuum-annealed at 500, 600, 700, 800 and 900 °C, respectively. X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), microindenter, Rockwell hardness tester and scratch tester were applied to investigate the microstructure, phase configuration, hardness and adhesion properties of as-deposited and annealed samples. The results indicated that there were two bonds, TiN and Si3N4, in all presently deposited TiSixNy thin films, that structure was nanocomposite of nanocrystalline (nc-) TiN embedded into amorphous Si3N4 matrices. Annealing treatment below 900 °C played a little role in microstructure and hardness of the coatings although it greatly affected those of steel substrates. The film-substrate adhesion strength was slightly increased, followed by an abrupt decrease with increasing annealing temperature. Its value got to the maximum at 600 °C. Annealing had little effect on the friction coefficient with its value varying in the range of 0.39-0.40. 相似文献