Properties of Reactive Magnetron Sputtered ITO Films without in-situ Substrate Heating and Post-deposition Annealing

Indium tin oxide (ITO) films were prepared on polyester, Si and glass substrate with relatively high deposition rate of above 0.9 nm/s by DC reactive magnetron sputtering technique at the sputtering pressure of 0.06 Pa system, respectively. The dependence of resistivity on deposition parameters, such as deposition rate, target-to-substrate distance (TSD), oxygen flow rate and sputtering time (thickness), has been investigated, together with the structural and the optical properties. It was revealed that all ITO films exhibited lattice expansion. The resistivity of ITO thin films shows significant substrate effect: much lower resistivity and broader process window have been reproducibly achieved for the deposition of ITO films onto polyester rather than those prepared on both Si and glass substrates. The films with resistivity of as low as 4.23 x 10^-4 Ω.cm and average transmittance of ～78% at wavelength of 400～700 nm have been achieved for the films on polyester at room temperature.

Surface Acoustic Wave Humidity Sensors Based on(1120) ZnO Piezoelectric Films Sputtered on R-Sapphire Substrates

ZnO films on R-sapphire substrates are prepared and characterized by x-ray diffraction and scanning electron microscopy, which indicate that the thin films are well crystallized with （1120） texture. Love wave and Rayleigh wave are used for fabrications of humidity sensors, which are excited in [1100] and [0001] directions of the （1120） ZnO piezoelectric films, respectively. The experimental results show that both kinds of sensors have good humidity response and repeatability, and the performances of the Love wave sensors are better than those of the Rayleigh wave sensors at room temperature. Moreover, the theoretical calculations of the mass sensitivity of the sensors are a/so carried out and the calculated results are in good agreement with the experimental measurements.

Reactively sputtered Fe_3 O_4 -based films for spintronics

Half metallic polycrystalline, epitaxial Fe3O4 films and Fe3O4 -based heterostructures for spintronics were fabricated by DC reactive magnetron sputtering. Large tunneling magnetoresistance was found in the polycrystalline Fe3O4 films and attributed to the insulating grain boundaries. The pinning effect of the moments at the grain boundaries leads to a significant exchange bias. Frozen interfacial/surface moments induce weak saturation of the high-field magnetoresistance. The films show a moment rotation related butterfly-shaped magnetoresistance. It was found that in the films, natural growth defects, antiphase boundaries, and magnetocrystalline anisotropy play important roles in high-order anisotropic magnetoresistance. Spin injection from Fe3O4 films to semiconductive Si and ZnO was measured to be 45% and 28.5%, respectively. The positive magnetoresistance in the Fe3O4 -based heterostructures is considered to be caused by a shift of the Fe3O4 e g ↑ band near the interface. Enhanced magnetization was observed in Fe3O4 /BiFeO 3 heterostructures experimentally and further proved by first principle calculations. The enhanced magnetization can be explained by spin moments of the thin BiFeO 3 layer substantially reversing into a ferromagnetic arrangement under a strong coupling that is principally induced by electronic orbital reconstruction at the interface.

Macro-superlubricity in sputtered MoS_(2)-based films by decreasing edge pinning effect

To date,MoS_(2) can only be achieved at microscale.Edge pinning effect caused by structure defects is the most obvious barrier to expand the size of structural superlubricity to macroscale.Herein,we plan to pin edge planes of MoS_(2) with nanospheres,and then the incommensurate structure can be formed between adjacent rolling nanoparticles to reduce friction.The sputtered MoS_(2) film was prepared by the physical vapor deposition(PVD)in advance.Then enough Cu_(2)O nanospheres(~40 nm)were generated in situ at the edge plane of MoS_(2) layers by liquid phase synthesis.An incommensurate structure(mismatch angle(θ)=8°)caused by MoS_(2) layers was formed before friction.The friction coefficient of the films(5 N,1,000 r/min)was~6.0×10^(−3) at the most.During friction,MoS_(2) layers pinned on numerous of Cu_(2)O nanoparticles reduced its edge pinning effect and decreased friction.Moreover,much more incommensurate was formed,developing macro-superlubricity.

Reactive Magnetron Sputtering of CN_x Thin Films on β-Si_3N_4 Substrates

Carbon nitride CN. thin films have been deposited on polycrystalline β-Si3N4 substrates by un-balanced magnetron sputtering in a nitrogen discharge. Both the film deposition rate and the nitrogen concentration decrease with substrate temperature increase in the range of 100~400℃The maximum of nitrogen content is 40 at. pct. Raman spectroscopy and atomic force mi-croscopy were used to characterize the bonding, microstructure and surface roughness of the films. Nanoindentation experiments exhibit a higher hardness of 70 GPa and an extremely elas-tic recovery of 85% at higher substrate temperature.

Enhanced Photoelectric Property of Mo-C Codoped TiO2 Films Deposited by RF Magnetron Cosputtering

Mo-C codoped TiO2 films were prepared by RF magnetron cosputtering. Ultraviolet-visible spectroscopy, atomic force microscopy, X-ray photoelectron spectroscopy, energy dispersive X-ray Analysis and X-Ray Diffraction were used to study the influences of codoping on energy gap, surface morphology, valence states of elements, ions content and crystal structure, respectively. The concentration of photogenerated carriers was measured by studying photocurrent density, while catalytic property was evaluated by observing degradation rate of methylene blue under visible light. A Mo-doped TiO2 film, whose content of Mo had been optimized in advance, was prepared and later used for subsequent comparisons with codoped samples. The result indicates that Mo-C codoping could curtail the energy gap and shift the absorption edge toward visible range. Under the illumination of visible light, codoped TiO2 films give rise to stronger photocurrent due to smaller band gaps. It is also found that Mo, C codoping results in a porous surface, whose area declines gradually with increasing carbon content. Carbon and Molybdenum doses were delicately optimized. Under the illumination of visible light, sample doped with 9.78at% carbon and 0.36at% Mo presents the strongest photocurrent which is about 8 times larger than undoped TiO2 films, and about 6 times larger than samples doped with Mo only.

Optimization of Gas Sensing Performance of Nanocrystalline SnO_2 Thin Films Synthesized by Magnetron Sputtering

Tin oxide （SnO2） is one of the most promising transparent conducting oxide materials, which is widely used in thin film gas sensors. We investigate the dependence of the deposition time on structural, morphologicaJ and hydrogen gas sensing properties of SnO2 thin films synthesized by dc magnetron sputtering. The deposited samples are characterized by XRD, SEM, AFM, surface area measurements and surface profiler. Also the H2 gas sensing properties of SnO2 deposited samples are performed against a wide range of operating temperature. The XRD analysis demonstrates that the degree of crystallinity of the deposited SnO2 films strongly depends on the deposition time. SEM and AFM analyses reveal that the size of nanoparticles or agglomerates, and both average and rms surface roughness is enhanced with the increasing deposition time. Also gas sensors based on these SnO2 nanolayers show an acceptable response to hydrogen at various operating temperatures.

Preparation and Characterization of Transparent Conductive Zinc Doped Tin Oxide Thin Films Prepared by Radio-frequency Magnetron Sputtering

High transparent and conductive thin films of zinc doped tin oxide （ZTO） were deposited on quartz substrates by the radio-frequency （RF） magnetron sputtering using a 12 wt% ZnO doped with 88 wt% SnO2 ceramic target.The effect of substrate temperature on the structural,electrical and optical performances of ZTO films has been studied.X-ray diffraction （XRD） results show that ZTO films possess tetragonal rutile structure with the preferred orientation of （101）.The surface morphology and roughness of the films was investigated by the atomic force microscope （AFM）.The electrical characteristic （including carrier concentration,Hall mobility and resistivity） and optical transmittance were studied by the Hall tester and UV- VIS,respectively.The highest carrier concentration of -1.144×1020 cm-3 and the Hall mobility of 7.018 cm2（V ·sec）-1 for the film with an average transmittance of about 80.0% in the visible region and the lowest resistivity of 1.116×10-2 Ω·cm were obtained when the ZTO films deposited at 250 oC.

Characterization of La-doped xBiInO_3(1-x)PbTiO_3 Piezoelectric Films Deposited by the Radio-Frequency Magnetron Sputtering Method

La-doped and undoped xBiIn03-（1 - x）PbTi03 （BI-PT） thin films are deposited on （101）SrRuO3/（lOO）Pt/（lO0） MgO substrates by the rf-magnetron sputtering method. The structures of the films are characterized by XRD and SEM, and the results indicate that the thin films are grown with mainly （100） oriented and columnar structures. The ferroelectricity and piezoelectricity of the BI-PT films are also measured, and the measured results illustrate that both performances are effectively improved by the La-doping with suitable concentrations. These results will open up wide potential applications of the films in electronic devices.

Optical and electrical properties of room temperature preparedα-IGZO thin films using an In_(2)Ga_(2)ZnO_(7) ceramic target

In this study,a high-purity In_(2)Ga_(2)ZnO_(7) ceramic target was used to deposit indium gallium zinc oxide(IGZO)films by RF magnetron sputtering technology.The microstructure,growth state,optical and electrical properties of the IGZO films were studied.The results showed that the surface of the IGZO film was uniform and smooth at room temperature.As the substrate temperature increased,the surface roughness of the film gradually increased.From room temperature to 300℃,all the films maintained amorphous phase and good thermal stabilities.Moreover,the transmission in the visible region decreased from 91.93%to 91.08%,and the band gap slightly decreased from 3.79 to 3.76 eV.The characterization of the film via atomic force microscope(AFM)and X-ray photoelectron spectroscopy(XPS)demonstrated that the film prepared at room temperature exhibited the lowest surface roughness and the largest content of oxygen vacancies.With the rise in temperature,the non-homogeneous particle distribution,increase in the surface roughness,and reduction in the number of oxygen vacancies resulted in lower performance of theα-IGZO film.Comprehensive analysis showed that the best optical and electrical properties can be obtained by depositing IGZO films at room temperature,which indicates their potential applications in flexible substrates.

Nano-sized Thin Films Fabricated by Ion Beam Sputtering and Its Properties

Nanoscale thick amorphous Ni-Cr alloy thin films were fabricated by low-energy ion beam sputtering technology; then the as-deposited samples experienced rapid thermal process to realize the transformation from amorphous to crystalline state. The film thickness was measured with a-stylus surface profiler, the structure and the compositions of the films were confirmed by low angle X-ray diffraction and scanning auger electron microprobe respectively, and the surface topography was characterized by scanning electron microscope and scanning probe microscope. Electrical property of the films was measured by fourpoint probe. The experimental results illustrate that the combined processes of ion beam sputtering and rajid thermal process are effective for fabrication nanoscale Ni-Cr alloy thin film with good properties.

Preparation and structural properties of thin carbon films by very-high-frequency magnetron sputtering

Growth and structural properties of thin a-C films prepared by the 60 MHz very-high-frequency（VHF） magnetron sputtering were investigated. The energy and flux of ions impinging the substrate were also analyzed. It is found that the thin a-C films prepared by the 60 MHz sputtering have a lower growth rate, a smooth surface, and more sp3 contents.These features are related to the higher ion energy and the lower ions flux onto the substrate. Therefore, the 60 MHz VHF sputtering is more suitable for the preparation of thin a-C film with more sp3 contents.

Effects of Substrate Temperature on Properties of Transparent Conductive Ta-Doped TiO_2 Films Deposited by Radio-Frequency Magnetron Sputtering

Ta-doped titanium dioxide films are deposited on fused quartz substrates using the rf magnetron sputtering technique at different substrate temperatures. After post-annealing at 550℃ in a vacuum, all the films are crystallized into the polycrystalline anatase TiO2 structure. The effects of substrate temperature from room temperature up to 350℃ on the structure, morphology, and photoelectric properties of Ta-doped titanium dioxide films are analyzed. The average transmittance in the visible region（400-800 nm） of all films is more than 73%.The resistivity decreases firstly and then increases moderately with the increasing substrate temperature. The polycrystalline film deposited at 150℃ exhibits a lowest resistivity of 7.7 × 10^-4Ω·cm with the highest carrier density of 1.1×10^21 cm^-3 and the Hall mobility of 7.4 cm^2·V^-1s^-1.

Initial growth and microstructure feature of Ag films prepared by very-high-frequency magnetron sputtering

The initial growth and microstructure feature of Ag films formation were investigated, which were prepared by using the very-high-frequency（VHF）（60 MHz） magnetron sputtering. Because of the moderate energy and very low flux density of ions impinging on the substrate, the evolutions of initial growth for Ag films formation were well controlled by varying the sputtering power. It was found that the initial growth of Ag films followed the island（Volmer—Weber, VW） growth mode, but before the island nucleation, the adsorption of Ag nanoparticles and the formation of Ag clusters dominated the growth. Therefore, the whole initial stages of Ag films formation included the adsorption of nanoparticles, the formation of clusters, the nucleation by the nanoparticles and clusters simultaneously, the islands formation, and the coalescence of islands.

High Ferroelectricities and High Curie Temperature of BiInO3PbTiO3Thin Films Deposited by RF Magnetron Sputtering Method

Properties of ferroelectric xBiInO3-（1-x）PbTiO3（xBI-（1-x）PT） thin films deposited on（101） SrRuO3/（200）Pt/（200） MgO substrates by rf magnetron sputtering method and effects of deposition conditions are investigated.The structures of the xBI-（1-x）PT films are characterized by x-ray diffraction and scanning electron microscopy.The results indicate that the thin films are grown with mainly（001） orientation. The chemical compositions of the films are analyzed by scanning electron probe and the results indicate that the loss phenomena of Pb and Bi elements depend on the pressure and temperature during the sputtering process.The sputtering parameters including target composition, substrate temperature, and gas pressure are adjusted to obtain optimum sputtering conditions. To decrease leakage currents,2 mol% La2 O3 is doped in the targets. The P-E hysteresis loops show that the optimized xBI-（1-x）PT（x = 0.24） film has high ferroelectricities with remnant polarization2 Pr = 80μC/cm2 and coercive electric field 2 EC = 300 kV/cm. The Curie temperature is about 640℃. The results show that the films have optimum performance and will have wide applications.

Structure and Magnetic Properties of Fe-N Films Prepared by Dual Ion Beam Sputtering

Fe-N films were prepared on Si substrate by dual ion beam sputtering (DIBS). It is found that the crystal structure of the films varies from α-Fe, to ε-Fe2-3N, ε-Fe2-3N +γ-Fe4N, and finally γ'-Fe4N with the increase in substrate temperature (TS). The magnetic properties of the films were investigated by a vibrating sample magnetometer (VSM). The structure of the films is insensitive to the ratios of N2/Ar in main ion source(MIS), and is mainly influenced by the substrate temperature (Ts).

Effect of Chromium on Structure and Tribological Properties of Hydrogenated Cr/a-C:H Films Prepared via a Reactive Magnetron Sputtering System

Hydrogenated Cr-incorporated carbon films （Cr/a-C：H） are deposited successfully by using a dc reactive mag- netron sputtering system. The structure and mechanical properties of the as-deposited Cr/a-C：H films are characterized systematically by field-emission scanning electron microscope, x-ray diffraction, Raman spectra, nanoindentation and scratch. It is shown that optimal Cr metal forms nanocrystalline carbide to improve the hardness, toughness and adhesion strength in the amorphous carbon matrix, which possesses relatively higher nano-hardness of 15. 7 CPa, elastic modulus of 126.8 GPa and best adhesion strength with critical load （Lc） of 36 N for the Cr/a-C：H film deposited at CH4 flow rate of 20sccm. The friction and wear behaviors of as-deposited Cr/a-C：H films are evaluated under both the ambient air and deionized water conditions. The results reveal that it can achieve superior low friction and anti-wear performance for the Cr/a-C：H film deposited at CH4 flow rate of 20sccm under the ambient air condition, and the friction coetllcient and wear rate tested in deionized water condition are relatively lower compared with those tested under the ambient air condition for each film. Superior combination of mechanical and tribological properties for the Cr/a-C：H film should be a good candidate for engineering applications.

Second phase effect on corrosion of nanostructured Mg-Zn-Ca dual-phase metallic glasses

Dual-phase metallic glasses(DP-MGs),a special member of the MGs family,often reveal unusual strength and ductility,yet,their corrosion behaviors are not understood.Here,we developed a nanostructured Mg_(57)Zn_(36)Ca_(7)(at.%)DP-MG and uncovered its corrosion mechanism in simulated body fluid(SBF)at the near-atomic scale utilizing transmission electron microscope(TEM)and atom probe tomography(APT).The 10-nm-wide Ca-rich amorphous phases allow oxygen propagation into the DP-MG,resulting in a micrometer thick hydroxides/oxides layer.This dense corrosion layer protects the DP-MG from further corrosion,enabling a corrosion rate that is 77%lower than that of Mg(99.99%purity).

Microstructure and Mechanical Property of Magnetron Sputtering Deposited DLC Film

A diamond-like carbon（DLC） film was deposited on YT14 substrate using magnetron sputtering（MS）. The surface morphologies, roughness and bonding spectra of obtained film were characterized using scanning electron microscopy（SEM）, atomic force microscopy（AFM）, and X-ray photoelectron spectroscopy（XPS）, respectively, and its mechanical property and bonding strength were measured using a nanoindentation and scratch tester, respectively. The results show that the C-enriched DLC film exhibits a denser microstructure and smoother surface with lower surface roughness of 21.8 nm. The ratio of C sp2 at 284.4 e V that corresponds to the diamond（111） and the C sp3 at 285.3 e V that corresponds to the diamond（220） plane for the as-received film is 0.36： 0.64, showing that the C sp3 has the high content. The hardness and Young＇s modulus of DLC film by nanoindentation are 8.534 41 and 142.158 1 GPa, respectively, and the corresponding bonding strength is 74.55 N by scratch test.

Synthesis of Flower-Like Bi2Te3 Nano Structure and Studying Its Structural and Thermo-electric Properties

Flower-like Bi2Te3 nanostructures were successfully synthesised for the first time by a simple magnetron technique or D.C. sputtering method. The phase and morphology of the products were characterized by X-ray diffraction （XRD）, manning electron microscope （SEM） and atomic force microscope （AFM）. It was found that the as-deposited Bi2Te3 has a well re-crystallized Rhombohedral phase and consisted of a wealth of flower-like structure, also the thermo-electric properties of Bi2Te3 were examined and we find that the Seebeck coefficient is 136.6μ volt/K.