Structural,Morphological and Electrical Properties of In-Doped Zinc Oxide Nanostructure Thin Films Grown on p-Type Gallium Nitride by Simultaneous Radio-Frequency Direct-Current Magnetron Co-Sputtering

Zinc oxide （ZnO） is one of the most promising and frequently used semiconductor materials. In-doped nanos- tructure ZnO thin films are grown on p-type gallium nitride substrates by employing the simultaneous rf and dc magnetron co-sputtering technique. The effect of In-doping on structural, morphological and electrical properties is studied. The different dopant concentrations are accomplished by varying the direct current power of the In target while keeping the fixed radio frequency power of the ZnO target through the co-sputtering deposition technique by using argon as the sputtering gas at ambient temperature. The structural analysis confirms that all the grown thin films preferentially orientate along the c-axis with the wurtzite hexagonal crystal structure without having any kind of In oxide phases. The presenting Zn, 0 and In elements＇ chemical compositions are identified with EDX mapping analysis of the deposited thin films and the calculated M ratio has been found to decrease with the increasing In power. The surface topographies of the grown thin films are examined with the atomic force microscope technique. The obtained results reveal that the grown film roughness increases with the In power. The Hall measurements ascertain that all the grown films have n-type conductivity and also the other electrical parameters such as resistivity,mobility and carrier concentration are analyzed.

Structural,optical,and electrical properties of Cu-doped ZrO_2 films prepared by magnetron co-sputtering

Copper （Cu）-doped ZrO2 （CZO） films with different Cu content （0 at.%- 8.07 at.%） are successfully deposited on Si （100） substrates by direct current （DC） and radio frequency （RF） magnetron co-sputtering. The influences of Cu content on structural, morphological, optical and electrical properties of CZO films are discussed in detail. The CZO films exhibit ZrO2 monocline （1^-11） preferred orientation, which indicates that Cu atoms are doped in ZrO2 host lattice. The crystallite size estimated form x-ray diffraction （XRD） increases by Cu doping, which accords with the result observed from the scanning electron microscope （SEM）. The electrical resistivity decreases from 2.63 Ω·cm to 1.48 Ω·cm with Cu doping content increasing, which indicates that the conductivity of CZO film is improved. However, the visible light transmittances decrease slightly by Cu doping and the optical band gap values decrease from 4.64 eV to 4.48 eV for CZO fihns.

The electrical,optical properties of AlSb polycrystalline thin films deposited by magnetron co-sputtering without annealing

In order to fabricate A1Sb polycrystalline thin films without post annealing, this paper studies a technology of magnetron co-sputtering onto intentionally heated substrate. It compares the structural characteristics and electrical properties of A1Sb films which are deposited at different substrate temperatures. It finds that the films prepared at a substrate temperature of 450 ℃ exhibit an enhanced grain growth with an average grain size of 21 nm and the lattice constant is 0.61562 nm that goes well with unstained lattice constant （0.61355 nm）. The ln（σdark） -1/T curves show that the conductivity activation energy is about 0.38 eV when the film is deposited at 450 ℃ without an annealing. The transmittance and reflectance spectra show that the film deposited at 450 ℃ has an optical band gap of 1.6 eV. These results indicate that we have prepared A1Sb polycrystalline films which do not need a post annealing.

Preparation,structure and ferromagnetic properties of the nanocrystalline Ti_(1-x)Mn_xO_2 thin films grown by radio frequency magnetron co-sputtering

This paper reported that the Mn-doped TiO2 films were prepared by radio frequency （RF） magnetron cosputtering. X-ray diffraction measurements indicate that the samples are easy to form the futile structure, and the sizes of the crystal grains grow big and big as the Mn concentration increases. X-ray photoemlssion spectroscopy measurements and high resolution transmission electron microscope photographs confirm that the manganese ions have been effectively doped into the TiO2 crystal when the Mn concentration is lower than 21%. The magnetic property measurements show that the Ti1-xMnxO2 （x = 0.21） films are ferromagnetic at room temperature, and the saturation magnetization, coercivity, and saturation field are 16.0 emu/cm^3, 167.5 × 80 A/m and 3740 × 80 A/m at room temperature, respectively. The room-temperature ferromagnetism of the films can be attributed to the new futile Ti1-xMnxO2 structure formed by the substitution of Mn^4＋ for Ti^4＋ into the TiO2 crystal .lattice, and could be explained by O vacancy （Vo）-enhanced ferromagnetism model.

Formation of Zr-contained Amorphous Alloy Films by Magnetron Co-sputtering

In order to explore the application of magnetron co-sputtering in fabricating the amorphous alloy, Zr-contained amorphous films were prepared by this technique and investigated by scanning electron microscope, energy disperse spectroscopy and X-ray diffraction. The results show that the co-sputtered films are in fully amorphous state or with amorphous-nanocrystal 1 ine structure. The XRD patterns of the Zr-Cu and Zr-Ni amorphous films exhibit a double-peak phenomenon. There is a shift of diffusive peak with changing the sputtering current which is possibly attributed to the change of Zr-Ni and Zr-Cu intermetallic like short range orders. In addition, Zr-Cu-Ni ternary co-sputtered films have a sharper peak at high angle. The sputtering yield of element during co-sputtering ranks as Cu>Ni>Zr, which can be ascribed to the contribution of melting and boiling temperature, atomic size and electrical conductivity of elements.

Effects of Vanadium Content on Structure and Chemical State of TiVN Films Prepared by Reactive DC Magnetron Co-Sputtering

TiVN films were deposited on Si(100) wafers without external heating and biasing by reactive dc magnetron co-sputtering. Titanium and vanadium metals were used as sputtering targets. Ar and N2 gases were used as sputtering gas and reactive gas, respectively. The flow rates of Ar and N2 were 8 and 4 sccm, respectively. The Ti sputtering current (ITi) was kept constant at 0.6 Aand V sputtering current (IV) was varied from 0.4 to1.0 A. The deposition time for all the deposited films was 30 min. The effects of V sputtering current on the structure, surface and cross-sectional morphologies, and chemical composition and chemical state of the films were investigated by X-ray diffraction (XRD), atomic force microscopy (AFM) and field emission scanning electron microscopy (FE-SEM), and X-ray photoelectron spectroscopy (XPS), respectively. It was found that all the prepared film formed (Ti,V)N solid solution. The lattice parameter was found to decrease while crystallite size, RMS roughness and film thickness increased with increasing V sputtering current. High resolution XPS spectra of the Ti 2p, V 2p and N 1s revealed that the fraction of Ti-N and V-N bonds increased as the V sputtering current increased. However, the V-N bond was observed only at a high V sputtering current.

Effects of Titanium Sputtering Current on Structure and Morphology of TiZrN Films Prepared by Reactive DC Magnetron Co-Sputtering

TiZrN films were deposited on unheated Si (100) substrates by reactive dc magnetron co-sputtering. Titanium and zirconium metals were used as sputtering targets. Ar and N2 gas were used as sputtering gas and reactive gas, with the flow rates of 8 and 4 sccm, respectively. The Zr sputtering current was fixed at 0.6 A and Ti sputtering current varied from 0.6 to 1.2 A. The deposition time for all the deposited films was 60 min. The effects of Ti sputtering current on the structure and morphology of the films were investigated by X-ray diffraction (XRD), atomic force microscopy (AFM), field emission scanning electron microscopy (FE-SEM) and transmission electron microscopy (TEM). It was found that all the prepared films were (Ti,Zr)N solid solution. Furthermore, the lattice parameter was found to decrease whereas the crystallite size, RMS roughness and film thickness increased with increasing Ti sputtering current. As a result, the crystallinity of the films increased what is in agreement with XRD results.

Continuous compositional spread investigation of SiC-based thin films prepared by MW-ECR plasma enhanced magnetron co-sputtering

A kind of combinatorial material methodology,also known as continuous compositional spread method,was employed to investigate the relationship between the optical band gap and composition of SiC thin films.A wide range of SixCy thin films with different carbon contents have been successfully deposited in a single deposition by carefully arranging the sample position on the substrate holder.The films were characterized by surface profiler,x-ray photoelectron spectroscopy,ultraviolet-visible spectroscopy,fourier transform infrared spectroscopy and Raman spectroscopy.The carbon content y increases linearly from 0.28 to 0.72 while the sample position changed from 85 to 175 mm,the optical band gap changed between 1.27 and 1.99 eV,the maximum value corresponded to the stoichiometric SiC sample at the position of 130 mm,which has the highest Si?C bond density of 11.7×10^22 cm^-3.The C poor and C rich SixCy samples with y value less and larger than 0.5 were obtained while samples deviated from the position 130 mm,the optical band gap decreased with the Si?C bond density.

Magnetron co-sputtering synthesis and nanoindentation studies of nanocrystalline(TiZrHf)_(x)(NbTa)_(1–x)high-entropy alloy thin films

Refractory high-entropy alloys(HEAs)possess many useful properties such as high strength and high-temperature stability.So far,most studies on refractory HEAs have been limited to a few well-known compositions and on their coarse-grain bulk forms.Here we fabricate nanocrystalline(TiZrHf)_(x)(NbTa)_(1−x)HEA thin films with a large range of compositions(x=0.07–0.90)by the direct current(DC)magnetron co-sputtering technique and measure their mechanical properties using the nanoindentation method.All the as-deposited HEA thin films show a solid-solution body-centered cubic(bcc)structure.As the compositional ratio(x)increases,the elastic modulus decreases from 153 to 123 GPa,following the trend of the rule of mixture.As x increases,the hardness first decreases from 6.5 GPa(x=0.07)to the lowest value(4.6 GPa,x=0.48)and then increases to the highest value(7.1 GPa,x=0.90),showing a concave trend.The change in hardness might be attributed to the combinational influence caused by the atomic size and modulus effects,as well as the texture effect.The authors also propose a few open questions for future studies on this and related HEA systems.

Wear Resistance of TiN_x/CF_y Coatings Deposited by RF Magnetron Co-Sputtering

TiN x/CF y composite coatings were prepared by RF magnetron co-sputtering using twin cylindrical tube targets with Ar and N 2 mixtures.The composition of the coatings deposited at various positions was analyzed by X-ray photoelectron spectroscopy（XPS） and Rutherford back-scattering spectrometry（RBS）.The results revealed that the composition of the deposited coatings has a wide range of TiN x and CFy contents at different deposition positions,which leads to different structures and performances.The hardness of the composite coatings increases from 32 to 1603 HV with increasing the TiN x concentration.The static contact angle of water ranges from 20° to 102° and decreases upon the incorporation of more TiN x into the CF y polymer.The presence of the CF y groups enhances the contact angle between the coating and the solutions dropped onto it,which could effectively protect the coating from corrosion and improve the wear resistance properties in high relative humidity（RH）.The brittleness of the coatings decreases due to the softness of the CF y component,which can bear most of the load and result in less probability of crack formation.XPS results demonstrate the existence of a Ti-（C N） chemical bond in the composite coatings,which improves the wear resistance of the coatings.It is indicated that the wear resistance of the TiN x/CF y coatings is independent of the hardness.However,these properties depend on the uniform structure and the existence of chemical bonding between the TiN x and CF y phases.Moreover,a specific ratio between the soft CF y phase and the hard TiN x phase can produce coatings with good wear resistance.

Surface Metallization of Glass Fiber(GF)/Polyetheretherketone(PEEK) Composite with Cu Coatings Deposited by Magnetron Sputtering and Electroplating

Surface metallization of glass fiber(GF)/polyetheretherketone(PEEK)[GF/PEEK] is conducted by coating copper using electroplating and magnetron sputtering and the properties are determined by X-ray diffraction(XRD), scanning electron microscopy(SEM), and electron backscatter diffraction(EBSD).The coating bonding strength is assessed by pull-out tests and scribing in accordance with GB/T 9286-1998.The results show that the Cu coating with a thickness of 30 μm deposited on GF/PEEK by magnetron sputtering has lower roughness, finer grain size, higher crystallinity, as well as better macroscopic compressive stress,bonding strength, and electrical conductivity than the Cu coating deposited by electroplating.

Structural and magnetic properties of micropolycrystalline cobalt thin films fabricated by direct current magnetron sputtering

Pure cobalt(Co)thin films were fabricated by direct current magnetron sputtering,and the effects of sputtering power and pres-sure on the microstructure and electromagnetic properties of the films were investigated.As the sputtering power increases from 15 to 60 W,the Co thin films transition from an amorphous to a polycrystalline state,accompanied by an increase in the intercrystal pore width.Simultaneously,the resistivity decreases from 276 to 99μΩ·cm,coercivity increases from 162 to 293 Oe,and in-plane magnetic aniso-tropy disappears.As the sputtering pressure decreases from 1.6 to 0.2 Pa,grain size significantly increases,resistivity significantly de-creases,and the coercivity significantly increases(from 67 to 280 Oe),which can be attributed to the increase in defect width.Corres-pondingly,a quantitative model for the coercivity of Co thin films was formulated.The polycrystalline films sputtered under pressures of 0.2 and 0.4 Pa exhibit significant in-plane magnetic anisotropy,which is primarily attributable to increased microstress.

High Permeability in Broadband of Co-sputtered [Fe-Fe_(20)Ni_(80)/Cr]_(n) Multilayer Films

To achieve high microwave permeability in wide-band for the micron-thick magnetic films,[Fe-Fe_(20)Ni_(80)/Cr]_(n) multilayer structure was proposed by co-sputtering Fe and FeNi to form the magnetic layers and Cr to form the interlayers.The multilayer structure contributes to the high permeability by reducing the coercivity and diminishing out-of-plane magnetization.The maximum imaginary permeability of[Fe-Fe_(20)Ni_(80)/Cr]_(n) multilayer film reaches a large value of 800 at 0.52 GHz even though its overall thickness exceeds 1μm.Besides,the magnetic resonance frequency of the multilayer film can be modulated from 0.52 to 1.35 GHz by adjusting the sputtering power of Fe from 0 to 86 W,and its bandwidth for μ’’>200(Δf) is as large as 2.0 GHz.The desirable broad Δf of magnetic permeability,which can be well fitted by the Landau-Lifshitz-Gilbert equations,is due to dual magnetic resonances originated from double magnetic phases of Fe and FeNi that are of different saturation magnetization.The micron-thick multilayer films with high permeability in extended waveband are promising candidate for electromagnetic noise suppression application.

Preparation of Light-Emitting Ytterbium-Doped Tantalum-Oxide Thin Films Using a Simple Co-Sputtering Method

Light-emitting ytterbium-doped tantalum-oxide thin films were prepared using a simple co-sputtering method for the first time. Sharp photoluminescence peaks having a wavelength of around 980 nm were observed from films annealed from 700&degC to 1000&degC for 10 to 40 min. The strongest intensity of the 980-nm peak was obtained from a film deposited using three ytterbium-oxide pellets and annealed at 800&degC for 20 min. Such rare-earth doped tantalum-oxide sputtered films can be used as high-refractive-index materials of autocloned photonic crystals that can be applied to novel light-emitting devices, and they will also be used as both anti-reflection and down-conversion layers for realizing high-efficiency silicon solar cells.

Photoluminescence and X-Ray Diffraction Properties of Europium and Silver Co-Doped Tantalum-Oxide Thin Films Deposited by Co-Sputtering

We fabricated europium and silver co-doped tantalum-oxide (Ta2O5:Eu, Ag) thin films using a simple co-sputtering method for the first time, and we evaluated their photoluminescence (PL) and X-ray diffraction (XRD) properties. We found that the most remarkable PL peak at a wavelength of 615 nm due to Eu3+ can be enhanced by Ag doping, and the strongest PL peak can be obtained from a Ta2O5:Eu, Ag thin film after annealing at 1000℃. Based on XRD measurements, we found that Ag2Ta8O21 crystalline phases produced by Ag doping are very important and Eu3TaO7 phases should be avoided in order to enhance the objective PL peak from our Ta2O5:Eu, Ag thin films.

Photoluminescence Properties of Europium and Cerium Co-Doped Tantalum-Oxide Thin Films Prepared Using Co-Sputtering Method

We fabricated europium and cerium co-doped tantalum (V) oxide (Ta2O5: Eu, Ce) thin films using our co-sputtering method for the first time, and evaluated photoluminescence (PL) properties of the films after annealing at 600°C - 1100°C for 20 min. Four remarkable PL peaks at wavelengths of 600, 620, 700, and 705 nm were observed from the film annealed at 900°C. The intensities of the 700- and 705-nm peaks due to the 5D0 → 7F4 transition of Eu3+ were much stronger than those of the 600-nm (5D0 → 7F1) and 620-nm (5D0 → 7F2) peaks of the film annealed at 900°C. It seems that energy transfer from Ce3+ to Eu3+ occurs in the film, and much energy is selectively used for the 5D0 →7F4 and 5D0 →?7F1?transitions. Such a Ta2O5: Eu, Ce co-sputtered thin film seems to be used as a multi-functional coating film having both anti-reflection and down-conversion effects for realizing a high-efficiency silicon solar cell.

Preparation of CuO-Ta<SUB>2</SUB>O<SUB>5</SUB>Composites Using a Simple Co-Sputtering Method

We prepared CuO-Ta2O5 composite films using our simple co-sputtering method for the first time. Four specimens were prepared from an as-deposited CuO-Ta2O5 sample by cutting it using a diamond- wire saw, and the specimens were subsequently annealed at 600°C - 900°C. The X-ray diffraction and photoluminescence (PL) of the annealed specimens were evaluated. The CuO-Ta2O5 film annealed at 600°C seemed to be primarily amorphous phase, and a sharp PL peak at a wavelength of 450 nm, due to the existence of Cu2+, was observed from the film. In contrast, the CuO-Ta2O5 films annealed at 700°C, 800°C, and 900°C seemed to be tetragonal CuTa2O6 phases. We expect that good-quality CuTa2O6 films can be obtained using our very simple co-sputtering method and subsequent annealing above 900°C. Such CuTa2O6 films can be used in chemisorptions conductometric gas sensors.

Photoluminescence Properties of Thulium and Cerium Co-Doped Tantalum-Oxide Films Prepared by Radio-Frequency Co-Sputtering

We prepared thulium and cerium co-doped tantalum-oxide (Ta2O5 :Tm, Ce) thin films by radiofrequency co-sputtering of Tm2O3 and CeO2 pellets on a Ta2O5 disc for the first time, and photoluminescence (PL) properties of the films annealed at 700°C, 800°C, 900°C, or 1000°C for 20 min were evaluated. PL peaks around a wavelength of 800 nm due to Tm3+?were observed for films annealed at 900°C or 1000°C. The peak intensities of films prepared using one Tm2O3 pellet and one CeO2 pellet were much stronger than those of films prepared using one Tm2O3 pellet and two CeO2 pellets or films prepared using two Tm2O3 pellets and one CeO2 pellet. To obtain the strongest PL intensity from the film, the proper Tm concentration was estimated to be around 1.0 mol%, and the proper Ce concentration was estimated to be around 1.3 mol%. Such Ta2O5:Tm, Ce co-sputtered thin films can be used as high-refractive-index materials of autocloned photonic crystals that can be applied to novel light-emitting devices, and they will also be used as anti-reflection and downconversion layers for realizing high-efficiency silicon solar cells.

Observation of Violet-Light Emission Band for Thulium-Doped Tantalum-Oxide Films Produced by Co-Sputtering

We prepared thulium-doped tantalum (V) oxide (Ta2O5:Tm) thin films using co-sputtering of two Tm2O3 pellets and a Ta2O5 disc, and we observed photoluminescence (PL) peaks not only around a wavelength of 800 nm due to the 3H4→3H6 transition of Tm3+ but also around a wavelength of 400 nm (violet) from the films after annealing for the first time. Comparatively narrow PL peaks around the wavelength of 400 nm were observed from the films annealed at 800°C and 900°C for 20 min. The peak intensity from the film annealed at 900°C was approximately four-times stronger than that from the film annealed at 800°C. The origin of the 400-nm peaks seems to be the same as our non-doped Ta2O5 thin films deposited using radio-frequency sputtering because we observe PL peaks around 400 - 430 nm from the Ta2O5 films. Such a Ta2O5:Tm co-sputtered thin film seems to be used as a multi-functional coating film having both anti-reflection and down-conversion effects for realizing a high-efficiency silicon solar cell.