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Although producing clusters by physical methods offers many benefits, low deposition rates have prevented cluster beam deposition techniques from being adopted more widely. The influence of the gas aerodynamics inside the condensation chamber of a magnetron cluster source on the cluster throughput is reported, leading to an improved understanding of the gas aerodynamics’ influence on cluster transport. In the first part of the paper the influence of the carrier gas’ inlet position on the cluster flux is studied. In particular, two inlet configurations were investigated, i.e. from the rear of the chamber and from within the magnetron sputtering source. It was found experimentally that the latter configuration can lead to an increased cluster flux, under the same conditions of gas pressure and power applied to the magnetron. This behaviour is explained with the help of simulations. In the second part of the paper, the gas dynamics behaviour inside four chamber shapes, namely two cylindrical shapes with different cross-section diameters and two conical shapes with different apex angles, was simulated. The modelling showed that the fraction of clusters successfully leaving the aggregation zone can be increased by up to 8 times from the worst to the best performing chamber geometries studied. Finally, the cluster throughput was determined experimentally using a quartz microbalance in two of the four chamber designs. It was found that the cluster flux increased up to one order of magnitude, reaching ~ 20 mg per hour for a condensation chamber with a smaller cross section and a conical exit. ispartof: Review Of Scientific Instruments vol:92 issue:3 ispartof: location:United States status: Published online

In this investigation, we studied electronic properties of the CdS/Zn1���xMgxO (x=0,0.15) interface using photoelectron spectroscopy. ZnO and (Zn,Mg)O films were deposited by magnetron sputtering from ceramic targets on thermally evaporated CdS. Valence-band offsets of ��EV=1.2��0.1 eV are determined for both interfaces. The gap difference of 0.3 eV between ZnO and Zn0.85Mg0.15O is therefore fully accommodated by a different conduction-band energy, which should be well suited for modulation doping in ZnO/(Zn,Mg)O heterostructures.

Ta [RT]/ CoFeB (2-50nm) [Ts = 500°C] /Ta [RT] films were grown on Silicon dioxide substrates by UHV magnetron sputtering system. The magnetic, microstructural and electrical properties were investigated as a function of CoFeB thickness (tCoFeB) at suitable substrate temperature (Ts). Further, we identify that, the strength of perpendicular coercivity (Hc┴)of the stacks mainly depends on the tCoFeB. Higher Hc┴ value of ≈ 564 Oe is observed for the thicker CoFeB film. The enhancement in the Hc┴ on increasing the film thickness upto 50 nm is due to the crystallization of CoFeB film at Ts = 500 °C. The morphological studies show larger grain size for thicker CoFeB film. A high value of electrical resistivity (ρ) is obtained by employing the standard four probe method, which further proves the amorphous nature of the CoFeB films. This Ta/CoFeB/Ta at Ts = 500 °C structures having high Hc┴ , large spin polarization (P) and low damping constant (α) values could be a capable candidate in the fabrication of novel spintronic devices.

Biosensor is one of the analytical devices that can detect chemical substance which contain biological component with a physicochemical detector. Optical biosensors are powerful alternative to conventional analytical techniques. Plasmonic biosensors are relying under optical biosensor categories. Previously, biosensor are normally use the tags and label-based detection and it will condition unbinding antigen towards the antibody such an example label is conjugated with one of the bio reactants, labeling can alter the biding properties. Plasmonic biosensor is a biosensor that uses Surface Plasmon Resonance (SPR) theory for its operation. Normally this biosensor is contains from a few components such as light source, prism, metal film, and detector. The metal film part is going to be discussed in this study where the SPR phenomenon will experienced. Gold nanoparticle is being used as the main material to fabricate the substrate and forming the thin film. Stated also gold have good chemical and mechanical stability which will affected the immobilization activity. For the exciting method use for surface plasmon, Krestchmann Configuration is being the most selected one. This obviously will produce a different kind of light reflection and dielectric properties. For the development of this plasmonic thin film the method is going to use is DC magnetron sputtering method and will be test on the rotational angle stage in order to get the optimum energy absorption that produce dark band as the intensity of light being absorb at certain angle. On the same time, simulation for SPR phenomenon oh this thin film was develop and resulting on produce graphical result on light refractive index

This research is described for fabricating molybdenum and sodium-doped molybdenum thin films by dc magnetron sputtering at room temperature for back contact of CIGS solar cells. Generally, the properties of thin films are dependent on deposition parameters. In this paper, we investigated the effect of argon (Ar) flow rate that aims for low resistivity and good adhesion. Films were deposited at different Ar flow rate in range of 10 - 40 sccm. The results present that the resistivity of the molybdenum and sodium-doped molybdenum thin films become higher with the increasing the Ar flow rate corresponding to the microstructure of roughness viewed by field emission scanning electron microscope (FESEM), lower Ar flow rate is smoother surface.

Silver (Ag) nanostructure films were fabricated by dc magnetron sputtering. The effect of deposition times were systematically studied in order to understand the relationship of morphology and surface enhanced fluorescence (SEF). The analysis of morphology by field emission scanning electron microscope (FE-SEM) exhibited the evolution of film growth process from nanoparticle, nanoisland and continuous film as a function of deposition time from 5-120 s. The SEF behaviour of the Rhodamine 6G (R6G) molecules deposited on the prepared Ag nanostructure films were investigated. The results of this study demonstrated that high fluorescence enhancement through the sized and nano-gap distance of the Ag nanoisland, compared with that of Ag films and silicon wafer substrate. In addition, our preparation SEF substrate has potential applications in chemical analysis and biosensor devices.

In this work, we presented a simple method for the growth of silver nanoparticles (Ag NPs) on glass and silicon substrates using the RF magnetron sputtering. The optical properties of Ag NPs deposited on glass and silicon substrates were studied. The surface plasmon resonance (SPR) peak of Ag NPs strongly depend on its size, shape and surrounding dielectric environment. The SPR peak of Ag NPs shows red shift with increase in the particle size as well as with the substrate effect.

We report controlled effect of Boron diffusion on annealing of Co60Fe20B20 (CoFeB) thin films grown on SiO2/Si(100) substrates using pulsed dc magnetron sputtering. X-ray diffraction studies indicated that the crystallization of CoFeB is achieved above 100°C via the formation of bcc CoFe with (110) preferred orientation. Saturation magnetization (µOMs) of the as-deposited film is found to be 1000 kA/m, which enhances upon annealing such that a value of µOMs of 1375 kA/m is observed in the sample annealed at 400°C while the coercivity decreases from 12 mT to 2 mT. A lowest value of 0.005±0.002 of the damping constant is evidenced for the sample annealed at 400°C. The tunability of the damping constant via the Boron out-diffusion from CFB achieved by controlling the annealing temperature is certainly important for spintronics device applications.

Mg-based alloys became a material of interest for biomedical applications. The major difficulty in the Mg-based alloy application is its rapid corrosion rate. Various coating methods are used to form a barrier layer onto Mg-based materials. In this work, a thin film of calcium phosphate was deposited on an Mg–0.8 at % Ca alloy using RF magnetron sputtering. As-deposited coatings were in an X-ray amorphous state. Post-deposition heat treatment resulted in the coating crystallization, exhibiting the pure HA phase. Heat-treatment at 450°C for 3 hours did not significantly change the coating integrity and adhesion strength to the Mg–0.8 at % Ca substrate. The Ca/P ratio, however, was changed from 1.85 for as-deposited to 2.00 for heat-treated samples. Both coating and substrate material after heat treatment exhibit preferential crystallographic growth in (002) direction with Tc(002) = 2.86 and 5.79, correspondingly.

Zirconium hafnium nitride (Zr-Hf-N) thin films were deposited on silicon wafer substrates by reactive co-magnetron sputtering with varying deposition time. The sputtering currents of Zr and Hf targets were kept constant at 800 and 600 mA, whereas the Ar and N2 gas flow rate were fixed at 36 and 3.5 sccm, respectively. The crystal structure determination revealed that the obtained Zr-Hf-N thin films can be indexed as ZrHfN2. Microstructure and surface morphology exhibit columnar structure. The nanohardness measurements suggested that the hardness was exponentially decreasing as the thickness was linearly increased.

We have prepared ultrathin films of CoFeB of thickness (∼3nm) by RF magnetron sputtering, on p-type Si substrate having few nm of native oxide layer. We have investigated the magneto-transport properties of the film in the current-in plane (CIP) geometry in the presence and absence of magnetic field. The magnetoresistance (MR=[R (H)-R (0)]/R (0) * 100%) was measured at five different bias current (ranging from 1 µA to 5 mA) in longitudinal (I parallel H) and transverse (I perpendicular H) configurations with H varying from 0 kOe to 90 kOe at room temperature (300 K). Anisotropy in the MR was also observed with 3% MR in longitudinal configuration and 6% MR in transverse configuration. At high bias current (5 mA), MR was found to be negative in both cases. The bias dependence is expected to be due to magnetic field control of impact ionization of carriers near the FM/SC interface. Also the anisotropy in MR seems to be different from the conventional anisotropic magnetoresistance (AMR).

In the present work, we describe the synthesis and electrochromic (EC) properties of electrode material made of zinc oxide (ZnO) nano-pebbles. Highly ordered nanocrystalline nanoporous ZnO nano-pebbles electrode with crystalline hexagonal structure was synthesized on the ITO coated glass substrate using RF magnetron sputtering in a reactive atmosphere (Ar:O2::2:3) at room temperature (RT). The EC behavior of the active electrode was analyzed using UV-Vis spectroscopy and cyclic voltammetry (CV). The cyclic Voltammogram revealed the highly reversible redox characteristics with good cyclic stability at least upto 500 cycles. The proposed architecture, {Glass/ITO/ZnO nano-pebbles/1MKCl/ITO/glass} was found to be electrochemically active and exhibits wide optical modulation (26%), high reversible process, and good cyclic stability. The cathodic coloration ZnO electrode may be a potential candidate for novel and cheap energy efficient device and provide the indoor comfort with financial benefits.

Current work describes the production of multi-component single-layer and multi-layer coatings by pulsed magnetron sputtering. The study scrutinizes the coatings in terms of their composition (X-ray diffraction analysis, XRD) and microstructure (transmission electron microscopy, TEM). The results demonstrate that the multi-component single-layer Al-Si-N coatings have nanocrystalline structure, while all the layers of the multi-layer Al-Si-N/Al-Si-0 coatings are amorphous due to the ingress of oxygen.

Light trapping is critical, particularly in thin film solar cells, in order to increase light absorption and hence overall cell efficiency. Plasmonic metal nanoparticles are of great interest for light trapping in thin film solar cells. Metal nanoparticles support surface Plasmon modes, which are used to couple light into the optical modes of semiconductor. The surface plasmons can enhance the spectral response of thin film cells over the entire solar spectrum. Silver nanoparticles can be used as light scattering elements on top and as a plasmonic back reflector structure at rear side of cell for enhancing solar cell energy conversion efficiency. The objective of our work is to gain more insight into the optical and structural properties of silver nanoparticles films and their effect on the performance of solar cells. Self-assembled silver nanoparticles(NPs) were formed by solid state dewetting (SSD) of thin silver film of variable thickness (12-34 nm), deposited using RF magnetron sputtering on various substrates glass and polished crystalline silicon (c-Si) substrates. The silver thin films were subsequently annealed at 400°C for 1 hour to form Ag NPs. Silver thin films with thickness of 12 nm have nanoparticles with average diameter of 50 nm with a roughly circular shape. We found that with increasing thickness of silver thin films the size of nanoparticles increases and the shape becomes more irregular.

Low period W/B4C multilayers are fabricated using magnetron sputtering system. The periods of multilayer are d ∼1.84 to 1.53 nm at a fixed number of layer pairs N = 400. Multilayers are characterized using hard x-ray reflectivity (XRR) at 20 keV and transmission electron microscope (TEM). XRR results well correlated with TEM observations. The measured structural parameters reveal good quality of multilayer structure. At 20 keV, measured reflectivities are 55% and 26 % for MLs with d ∼ 1.84 nm and 1.53 nm, respectively.

Efficient injection of charge from metal electrodes into semiconductors is of paramount importance to obtain high performance optoelectronic devices. The quality of the interface between the electrode and the semiconductor must, therefore, be carefully controlled. The case of organic semiconductors presents specific problems: ambient deposition techniques, such as solution processing, restrict the choice of electrodes to those not prone to oxidation, limiting potential applications. Additionally, damage to the semiconductor in sputter coating or high temperature thermal evaporation poses an obstacle to the use of many device-relevant metals as top electrodes in vertical metal–semiconductor–metal structures, making it preferable to use them as bottom electrodes. Here, we propose a possible solution to these problems by implementing graphene-passivated nickel as an air stable bottom electrode in vertical devices comprising organic semiconductors. We use these passivated layers as hole-injecting bottom electrodes, and we show that efficient charge injection can be achieved into standard organic semiconducting polymers, owing to an oxide free nickel/graphene/polymer interface. Crucially, we fabricate our electrodes with low roughness, which, in turn, allows us to produce large area devices (of the order of millimeter squares) without electrical shorts occurring. Our results make these graphene-passivated ferromagnetic electrodes a promising approach for large area organic optoelectronic and spintronic devices. Organic semiconductors serve as a platform for (opto)electronic devices with tunable characteristics by molecular design, enabling versatile device integration, and processing strategies.1 However, ambient processing techniques such as solution processing can facilitate oxidation of metal contacts, resulting in an uncontrolled electronic interface, which is deleterious to performance in semiconductor devices.2,3 New techniques are, therefore, required to control the interface between organic semiconductors and oxidizing metals while maintaining the possibility of solution processing. Graphene has been shown to act as an atomically thin permeation barrier.4–6 Graphene grown via chemical vapor deposition (CVD) directly on the surface of strongly interacting7 catalytic metals, such as Ni, Co, or Fe, acts as a barrier layer to prevent oxidation.8–11 These oxide-free ferromagnetic interfaces have been shown to hold significant benefits within the field of spintronics,12,13 as they enable oxidative fabrication processes, such as solution processing9,10 or atomic layer deposition,14 to be used to fabricate devices with a wider range of relevant materials. One appealing possibility would be to develop graphene-passivated ferromagnets as electrodes9,10 for organic semiconductor spintronics,15–18 where the quality of the electronic interface between the ferromagnetic electrode and the organic semiconductor is of paramount importance.19,20 Another important advantage of an ambient-stable ferromagnetic layer is that it can be used as a bottom electrode in vertical metal-organic semiconductor–metal structures, allowing one to employ techniques such as sputtering to obtain high quality and thickness-controlled metal layers or multi-layers; note that sputtering cannot be used for top-electrodes as it would destroy21 the organic semiconductor. Previous reports using graphene passivated ferromagnets as electrodes for organic semiconductor devices have studied the spin injection properties10 as well as charge injection in lateral organic semiconductor field effect transistors.9 In this work, we investigate few-layer graphene-passivated nickel (Ni/FLG) as a bottom electrode for injection of holes into organic semiconducting polymers in a vertical device structure, demonstrating efficient injection into two standard semiconducting polymers deposited from solution and in air, directly on top of Ni/FLG. Compared to previous reports on graphene-passivated ferromagnetic electrodes, where lithographic techniques had to be used in order to produce micrometer-sized features,8–10,12,14 here, we were able to produce working devices with several orders of magnitude larger active area (4.5 mm2). Our results are, thus, encouraging for the further development of organic optoelectronic and spintronic devices processed from solution under ambient conditions. Nickel was initially sputtered on thermally oxidized silicon wafers, producing films with a thickness of 150 nm. FLG domains were grown on such sputtered Ni films in a custom low-pressure Chemical Vapor Deposition (CVD) reactor (base pressure ∼1 × 10−6 mbar). All substrates were cleaned by sonicating in acetone followed by isopropyl alcohol and blow-dried with a nitrogen gun before loading. Samples were heated to approximately 450 °C using a resistive heater (temperature measurements by a K-type thermocouple) with a rapid ramp rate of 100 °C/min and annealed at ∼1 mbar of H2 for 10 min. This reduces the native oxide prior to graphene growth. After annealing, the H2 flow was stopped and the chamber was evacuated back to approximately base pressure over a period of 5 min. For graphene growth, C2H2 gas was gradually introduced into the reactor via a mass flow controller by incrementally increasing the flow rate over 5 min to achieve a partial pressure of C2H2 of 2.5 × 10−4 mbar. Subsequently, the samples were held at 450 °C in 2.5 × 10−4 mbar of C2H2 for a further 25 min, before rapid cooling (initially ∼300 °C/min) while maintaining the C2H2 flow. All gases were stopped once room temperature had been reached. Upon graphene growth, a roughening of the Ni sputtered on thermally oxidized Si was observed, with an RMS = 67 nm [Fig. 1(a)]. The roughness was found to increase with increasing growth temperature. The roughening of Ni upon graphene growth is explained by grain growth in the sputtered Ni films, occurring at high temperatures during the CVD process: under these conditions, the internal forces in the film are larger than those between the film and the substrate, and diffusion of the film material is appreciable.

In this paper, thin film of ZnO nanoparticles deposited on a planar Si (100) and a textured Si (100) substrate are investigated. Chemical etching is used to prepare textured Si substrate and RF magnetron sputtering is used to deposite ZnO thin films. The surface morphology and reflectance are studied with SEM and UV-VIS Spectroscopy, respectively. Structural morphology of the etched wafer indicate random pyramidal structures. Optical study indicates a significant reduction in reflectance for textured silicon (TS) heterojunction in comparison to planar Si (PS) heterojunction. This study promotes the study of heterojunction devices and surface texturing for light management in various optoelectronic devices.

A plasma model was established to calculate the discharge properties during TaN and TiN sputter deposition at low pressure conditions (about 2 mTorr). The plasma model is zero dimensional and includes major reactions between electrons and argon/nitrogen gases. The gas flow rates are varied for nitrogen (up to 9 sccm) and always 10 sccm for argon. The calculated electron temperature increases from 4.15 to 4.35 eV at 370 W magnetron power. The predicted electron density is about 109 cm−3, and increases with nitrogen flow rate. The predicted electron temperature and density values agree well with measurements for plasma at similar power level and pressure conditions. As nitrogen flow rate increases, the N atom and N2* densities both increase linearly, at the order of 1011 cm−3.

Thin film coatings TiSiN, TiAlSiN were deposited on WC-Co milling inserts using RF magnetron sputtering. The machinability studies of maraging steel is carried out using thin film coatings of TiSiN TiAlSiN. The maching parameters of cutting speed, feed rate and depth of cut will be varied to analyse machining responses such as surface roughness and cutting force. The performance of each coating will be evaluated and compared along with tool wear and tool life. A Taguchi based grey relational analysis will be used to optimize the machining parameters and analysis of variance (ANOVA) is used to find the most significant factor.Thin film coatings TiSiN, TiAlSiN were deposited on WC-Co milling inserts using RF magnetron sputtering. The machinability studies of maraging steel is carried out using thin film coatings of TiSiN TiAlSiN. The maching parameters of cutting speed, feed rate and depth of cut will be varied to analyse machining responses such as surface roughness and cutting force. The performance of each coating will be evaluated and compared along with tool wear and tool life. A Taguchi based grey relational analysis will be used to optimize the machining parameters and analysis of variance (ANOVA) is used to find the most significant factor.

The article describes the study results of structure and properties of high-entropy thin-film coatings made of FeNiCoAlW material with thermoelastic transformations, which were obtained by magnetron sputtering. The studied coating with a thickness of 600 nm with a smooth surface and a homogeneous microstructure has a fairly high hardness due to the formation of a nanocrystalline structure. The FeNiCoAlW coating shows good ductility when tested for nanoindentation, which is confirmed by the results of friction-cyclic tests. The study results indicate that FeNiCoAlW coatings obtained by magnetron sputtering can substitute the traditional coatings made of carbides and nitrides of transition metals for some special applications.

Single phase, epitaxial GaN films have been grown at 700 oC on c-sapphire by rf magnetron sputtering using a GaAs target, with 100 % and 10 % N2 in Ar-N2 atmosphere. High resolution XRD measurements reveal significant differences in the strain present in the two films. Electrical measurements show low resistivity ∼2 x 10−3 Ω-cm for the film grown with 10 % N2, compared to the high resistivity (≳ 105 Ω-cm) of the film grown with 100 % N2 in sputtering atmosphere. Optical studies reveal significant difference in band gap of the two films and free carrier features in NIR due to the high electron concentration of 1.2 x 1020 cm-3 in the film grown with 10 % N2. XPS studies reveal the absence of As but presence of similar levels of oxygen impurity in the two films. The film grown with 10 % N2 shows much smaller N/Ga ratio and the presence of uncoordinated Ga, indicating that nitrogen vacancies are likely to be responsible for its high conductivity.

Rare-earth based manganese oxide films having optimized compositions La0.7Ca0.3MnO3(LCMO) are fabricated using R.F Sputtering technique on n-type Si/SiO2substrate at ambient temperature and 40 millibar oxygen partial pressure with subsequent post annealing at 900°C for a duration of 12 hours. The polycrystalline LCMO composite target is synthesized using conventional solid- state reaction route. Positive magneto-resistance is observed in studied hole doped manganite at room temperature. This shows that the present LCMO is paramagnetic at room temperature. X-Ray diffraction shows that sample is crystallized in single phase and SEM micrographs and EDS report depicts the surface morphology of LCMO. Resistance measurements are done using standard four probe technique at 300 K and at zero field,0.5 T and 1.5 T. Magnetoresistance (MR) comes out to be about 10.28% at 1.5 tesla, which is remarkable in itself.

We present a comparative study of synthesis and characterization aluminum nitride (AlN) thin films deposited using a direct current (dc) and a radio frequency (rf) magnetron sputtering (MS)process. In both cases transparent and amorphous AlN phases are formed, albeit at quite different partial N2 gas flows. It appears that the formation of amorphous and transparent AlN phase takes place from a transient state of Al target and the deposition rate reduced by about 50-70% as compared to pure Al metal. However, overall deposition rates were found to be higher in the dcMS process. It was found that the formation of transparent AlN phase is very sensitive to N2 flow in the rfMS process but not so much in the dcMS process. Amorphous and transparent AlN thin films grown using the dcMS and rfMS processes were studied using x-ray diffraction and N K-edge x-ray absorption spectroscopy techniques. Obtained results are presented and discussed in this work.

The results of a study on dielectric relaxation in thin layers of amorphous MoTe2 using dielectric spectroscopy are presented. Dipole-relaxation polarization has been observed. The activation energy of the relaxation process was calculated to be Ea = (0.44±0.02) eV. The dispersion of the dielectric constant and the presence of a maximum of dielectric losses in the studied MoTe2 films may be due to the disordered structure of the amorphous material and the presence of chalcogen vacancies.

In the present work the effect of variation in nitrogen concentration on magnetic properties of Al-N alloy thin film has been reported. The AlN films were deposited by RF magnetron sputtering of Al target using a gas mixture of ultra-high pure (99.999%) Ar and N2. Five films were deposited, by varying the nitrogen concentration in gas mixture as 0% (Pure Ar), 5%, 20%, 50% & 100% (Pure N2). All the five films are amorphous in nature. The density of the films increases from 2.18 gm/cc (close to bulk Al density) to 3.24 gm/cc (close to bulk AlN density), indicating increase in formation of Al-N sites with increasing nitrogen concentration. Magnetization measurement on all the five films exhibit hysteresis loop along with paramagnetic or diamagnetic contribution. The observed variation in magnetic properties with increasing nitrogen concentration has been discussed.

Semiconducting layered materials such as transition metal dichalcogenides (TMDCs) have emerged as a significant class of electronic materials. The most representative material MoS2 in this class has been utilized to enhance the performance parameters of electronic devices in the numerous applications including in the field of photovoltaics, sensing, TFTs, etc. Here we study the MoS2 nanopillars grown on different substrates by using pulsed DC magnetron sputtering technique. Using Atomic Force Microscopy (AFM), Scanning Electron Microscopy (SEM) and Energy Dispersive Spectroscopy (EDS) analysis. We have been able to observe the role of growth conditions on morphology and geometrical size of the nanopillars. The control on sputtering conditions resulted in self grown nanopillar array on quartz substrates. Considering the correlation between the influences of substrate roughness and sputtering power on the growth of MoS2 nanopillars, we have found out a straight forward and lithography free technique to grow nanopillars of MoS2. Growth of MoS2 nanopillars through sputtering technique opens up a pathway to solve the challenge of scalability at room temperature for MoS2 nanostructure based devices.

The effects of different sputtering power on the physical and electrical properties of Gadolinium oxide (Gd2O3) films grown by RF Magnetron sputtering is investigated in this paper. All the films were deposited at room temperature with varying sputtering power from 20 W to 80 W in 20 W steps. The composition of the films was studied by X-ray photo electron spectroscopy (XPS) while microstructural and morphological modifications were studied by Atomic Force Microscopy (AFM). The chemical composition of the film improved with increasing sputtering power and at higher powers, films exhibited excess oxygen concentration. The minimum flatband voltage shift and lowest effective oxide charge density values were obtained from MOS capacitor with Gd2O3 grown at 40 W power.

Tungsten disulfide, owing to its high theoretical specific capacitance is one of the most studied and promising candidates for electrochemical energy storage applications among various layered materials. Herein, we have fabricated WS2 thin films on silicon substrates by using reactive DC magnetron sputtering technique with metallic tungsten target and H2S as sulfur source at room temperature (Ar:H2S 2:1). For electrochemical application, the electrodes have been prepared in-situ using copper foam as current collector. The in-situ growth allows the films to form actively structured electrodes as well as provide an opportunity to study the morphological effect of electrodes on electrochemical performance. The morphological results depicted the growth of grainy WS2 thin films on current collector with an average roughness of 2.7 nm. Further, we have performed detailed electrochemical analysis and studied the supercapacitive properties of tungsten disulfide. We found the electric double layer capacitance of WS2 thin films to be 2.42 mF/cm2 with linear charge discharge characteristics. This high areal capacitance of WS2 thin films may be attributed to the contribution of metallic foam current collector which reduces the global equivalent series resistance of electrode-electrolyte system. Additionally, copper foam functions as a mechanical backbone and improves the charge carrier transport across the electrode.

This paper described the design, fabrication, and test results of Zinc Oxide (ZnO) thin films based ethanol (C2H5OH) sensor. Pure ZnO (c- axis oriented) thin films was prepared by RF magnetron sputtering techniques at room temperature on Silicon (Si)/Silicon dioxide (SiO2)substrate for gas sensing applications. Along with the ZnO thin film, Pt micro-heater, platinum resistance thermometer (PRT) and interdigited gold (Au) electrodes were also fabricated verticallyto make a complete C2H5OH sensor device. The layout design of platinum(Pt) microheater and PRT along with the interdigited electrodes is performed by the computor tool L-EDIT. The thermo-mechanical analysis of micr-heater was performed by the multi-physics simulator ANSYS. The deposited ZnO thin film is annealed at different temperatures in the range of 250 °C to 450 °C. The properties of annealed ZnO thin film was analyzed by using various charactirization techniques such as surface profilometer, XRD, EDX and SEM. A measurement set-up was also developed to measure the performance of Pt micro heater and the sensitivity of the sensor at differnet concentration of C2H5OH. The highest sensitivity of C2H5OH sensor was achieved at the operating temperature of 350 °C. The Ethanol sensor shows good performance in terms of stability, sensitivity, recovery, response, reversibility and repeatability in the concentration of C2H5OH ranging from 50 ppm to 200 ppm.

Transition-metal nitride (TMN) thin films are recognized as the leading electrode material for new generation, high- performance, stable, flexible, smart supercapacitor because these films exhibit wider voltage range, good sustainability and high electrical conductivity. Herein, we have deposited high quality thin film of metal nitride in controlled vacuum level by using reactive DC-magnetron sputtering for enhanced performance supercapacitor. TMN film was grown on 304 Stainless Steel (304 SS) substrate at 200° C for 30 minutes in Ar-N2 atmosphere. TMN film of VN@SS was tested as an electrode material in aqueous solutions of 1M KOH at various scan rates. Scanning Electron Microscopy (SEM) revealed the film thickness and confirm the nanoflake type structure for the TMN film, while composition was confirm by the EDAX attached with SEM. X-ray diffraction (XRD) showed the phase orientation and crystal structure of TMN film. These metal nitride based electrodes exhibited super hydrophilic nature (with contact angle 19° for VN@SS) in presence of used electrolytes and revealed enhanced volumetric capacitance with an excellent rate performance.

Multilayer structures containing dielectric/ metal/ dielectric layers have been deposited on glass and coated with ITO substrates using DC magnetron sputtering technique. The multilayer coating based on interference effects can be realized by stacking metal (Ag) as a sandwich between two a high index dielectric (V2O5) i.e. V2O5/Ag/ V2O5.·V2O5 thin layers have been deposited using reactive DC magnetron sputtering technique from the sputtering of vanadium target in Ar/O2 mixture. X-ray diffraction (XRD) has been confirmed that the deposited thin layers are composed mainly of V2O5 phase. The reflectance spectra from visible to NIR wavelengths (300-1100) nm of multilayers were recorded. These thin layers were transparent for visible spectrum 400 - 800 nm however reflecting IR radiations beyond 800 nm. The optical measurements for all the thin layers samples that were prepared, which based on V2O5/Ag/V2O5 multilayers structure with varying thickness 20,40,60,80 nm of top layer for V2O5 while 10,20 nm of middle layer (Ag) and bottom layer (V2O5) respectively. Result shows that, the ITO single and V2O5 (20nm) / Ag (10nm)/V2O5 (40nm) multilayer gave maximum transmittance about 92.4 % at 550 nm. Also NIR reflection of the multilayer coating is less than 10% in the VIS range and it enhanced to over 80% in the NIR range of V2O5 20nm)/Ag (10nm)/V2O5 (20nm) multilayer. The best performance was accomplished for the heat mirror with 10 nm of Ag thickness and 20nm of outer layer of V2O5.

We present systematic investigations of tuning magnetic anisotropy, domain structure, magnetic, structural and electrical transport properties of Fe1-xNix thin films. All the films were prepared by DC magnetron sputtering directly on Si (100) substrate maintained at different substrate temperatures (TS). Fe1-xNix films deposited at ambient temperature exhibit disordered structure. With increasing TS, the degree of L10 ordering enhanced up to 250°C and then decreased due to the formation of A1 phase. As a result, the average surface roughness increased and consequently the electrical resistivity decreased with increasing TS. Saturation magnetization (MS) and anisotropy energy (Ku) increased progressively with increasing Fe content and exhibited a maximum of 0.91 T and 0.52 MJ/m3, respectively, for Fe51Ni49 thin films prepared at TS = 250 °C. Magnetic domain studies confirmed the existence of in-plane niaxial magnetic anisotropy in L10 ordered FeNi films.

We have demonstrated the impact of fabrication of pyramidal structure on Silicon (Si) wafer substrate in ZnO/Si heterojunction on its structural and optical properties. The texture on Si substrate is obtained using wet etching method for different time durations. Patterns of photoresist have been used to get desired size of the structure. Scanning electron microscopy (SEM) of the samples shows a pyramidal structure on the surface of Si substrate. The thin film of ZnO material on p-type planar silicon (100) and textured Si (100) substrate has been deposited by using RF magnetron sputtering technique. ZnO thin films produce an anti reflection (AR) effect when deposited on silicon substrate. The structural and optical properties of ZnO/Si (TS) heterojunction were studied by x-ray diffraction (XRD) and UV-Vis spectrophotometer respectively. XRD patterns of the ZnO/Si and ZnO/Si (TS) heterojunctions show the orientation of the ZnO film fabricated on silicon substrate. Their reflectance spectra show reduction in reflectance proportional to increase in time duration of texturization. This study indicates that ZnO/Si (TS) heterojunction may be utilized in various heterojunction and photovoltaic devices for reduction in reflection of incident light.

Optical Emission Spectroscopy (OES) incorporated with the plasma models of glow discharge emission come to be a multipurpose technique of determination plasma parameters. In this work, we have studied the plasma electron temperature Te and electron density ne by OES of low-pressure argon plasma as function to different applied voltages and working pressure in the existence of vanadium target and argon (Ar) gas. The entire electrodes spacing is 5 cm with a flow ratio of 40 sccm. The spectral detection is performed with a spectrometer of wavelength range (200-900nm). The working pressure and applied voltage were 0.085-3.5mbar and 400-600 Voltes respectively. The method had been applied to assess the electron temperature and electron density is a Boltzmann plot method which preferred to amelioration the accuracy of the measurements. Results show for the plasma investigated a rising of the electron temperature when the applied voltage has been increased; while, the electron temperature decreases when the working pressure is increased. In another hand, electron density decreases with the increase in applied voltage and increases with the increase of working pressure. New diagnostic for types of plasmas demonstrates a dependable non-intrusive means of determining the absolute value for electron temperature and density with the least number of assumptions essential compared to other diagnostics approaches.

The features of structural state and the temperature-dependent properties of Co-W films deposited by magnetron sputtering directly on glass substrates, as well as on Ru buffer layer were investigated. It is shown that in the Co-W films on a glass, tungsten doping leads to the formation of a highly textured state of hcp crystallites with an axis perpendicular to the sample plane. Using data on the temperature change of magnetic properties, it is concluded that the presence of a crystalline texture is the cause of macroscopic perpendicular anisotropy, which leads to the formation of a magnetic structure of the “trans-critical state” type in a certain range of compositions. The Ru buffer layer slows down compositional structural transformations, which has a corresponding effect on the magnetic properties of the films.

The topological kagome metal CoSn hosts orbital-selective Dirac bands and very flat bands near the Fermi energy that lead to a range of exotic phenomena, such as fractional quantum Hall states. In this work, we report the synthesis of high-quality epitaxial (0001) CoSn films by magnetron sputtering. Comprehensive structural characterizations demonstrate high crystalline quality with low disorder, sharp interfaces, and a smooth surface. Complementary magnetic and transport properties show a paramagnetic, metallic ground state as seen in bulk. Our work creates a synthetic foundation to investigate and utilize rich topological physics in CoSn thin films and heterostructures.

Herein, pure ZnO, Ag-doped ZnO, and Cu-doped ZnO films with excellent ultrafast (femtosecond) nonlinear absorption/limiting behavior were deposited on quartz substrates by magnetron sputtering. From the open-aperture Z-scan result, under femtosecond pulses, the strong two-photon absorption (TPA) behavior of metal-doped ZnO was found, and the absorption coefficient was found to be several times that of pure ZnO, which will expand the design and application strategies of metal-doped wide-gap semiconductor materials in the field of nonlinear devices. Moreover, the samples exhibited superior optical limiting behavior with respect to the optical modulation characteristics of the input–output laser. The mechanism of optical limiting effects is induced by the TPA-induced reverse saturable absorption of the deep level and low excited state processes.

Gold-tantalum alloy films are of interest for biomedical and magnetically-assisted inertial confinement fusion applications. Here, we systematically study the effects of substrate tilt ( 0°–80°) and negative substrate bias (0–100 V) on properties of ≲3- μm-thick films deposited by high-power impulse magnetron sputtering (HiPIMS) from a Au–Ta alloy target (with 80 at. % of Ta). Results reveal that, for all the substrate bias values studied, an increase in substrate tilt leads to a monotonic decrease in film thickness, density, residual compressive stress, and electrical conductivity. Larger substrate bias favors the formation of a body-centered cubic phase, with films exhibiting lower column tilt and higher density, electrical conductivity, and residual compressive stress. These changes are attributed to metal atom ionization effects, based on the lack of correlation with distributions of landing energies and incident angles of depositing species as calculated by Monte Carlo simulations of ballistic collisions and gas phase atomic transport. By varying substrate tilt and bias in HiPIMS deposition, properties of Au–Ta alloy films can be controlled in a very wide range, including residual stress from −2 to +0.5 GPa, density from 12 to 17 g/ cm3, and the electrical resistivity from 50 to 4500 μΩ cm, enabling optimum deposition conditions to be selected for specific applications.

The thrusts induced by the 45-mm-diameter DC and high power impulse magnetron sputtering [DC magnetron sputtering (DCMS) and high power impulse magnetron sputtering (HiPIMS)] sources are assessed by using the pendulum thrust balance, where the instantaneous discharge power for the HiPIMS is two orders of magnitude larger than that for the DCMS. The temporally averaged power of the HiPIMS is chosen as 50–150 W, being similar to the DCMS, by adjusting the duty cycle. The thrust-to-power ratios of 9.1 and 3.7 mN/kW are obtained for the DCMS and HiPIMS, respectively, by ejecting the copper target material via sputtering. A comparison between the thrust and the deposition rate of the copper film on a substrate implies that the flux and the velocity of the ejected material for the DCMS are larger and lower than those for the HiPIMS, respectively.

Many applications of boron carbide ( B4C) films entail deposition on non-planar substrates, necessitating a better understanding of oblique angle deposition phenomena. Here, we systematically study the effect of substrate tilt on properties of B4C films with thicknesses up to 10 μm deposited by direct current magnetron sputtering. Results show that all films are amorphous and columnar with an average column width of ∼100 nm, independent of substrate tilt. Column tilt angles are limited to ∼20° even for substrate tilt of 80°. Film density, residual stress, and the refractive index weakly (within ≲20%) depend on substrate tilt. Oxygen impurities bond preferentially with carbon atoms in inter-columnar regions. Substrate tilt has a major effect on mechanical properties that decrease by ∼50%, suggesting weak interconnection between nano-columns. Implications of these observations for the deposition onto non-planar substrates are discussed.

This work demonstrates the synthesis of fcc-Co derived from an isostructural Co4N phase. When deposited at high substrate temperature ( Ts) or thermal annealing ( Ta) above 573 K, the out-diffusion of N from fcc- Co4N occurs, leaving behind a high purity fcc-Co phase. Generally, Co grows in a hcp structure, and a hcp to fcc-Co transformation can be facilitated at high temperature or pressure. The proposed route by nitridation and diffusion of N not only brings down the transition temperature but an impurity present in the form of hcp-Co can be avoided altogether as well. Oriented Co4N(111) thin films were grown using a CrN(111) template on a quartz substrate using dc magnetron sputtering. Samples were grown at different Ts or room temperature grown Co4N samples were annealed at different Ta. Analysis using x-ray diffraction, N K-edge x-ray absorption, x-ray photoelectron, and secondary ion mass spectroscopy confirmed the formation of fcc- Co4N or fcc-Co phases. Furthermore, it was found that Co–N bonding and N concentration get significantly reduced at high Ts or Ta due to exceptionally high N self-diffusion taking place in Co4N. Magnetic measurements using ex situ and in situ magneto-optical Kerr effect showed differences in saturation behavior and coercivity of Co4N and fcc-Co samples. By combining structural, electronic, and magnetization measurements, it has been observed that a high purity fcc-Co can be conveniently derived from the isostructural Co4N aided by an exceptionally high N self-diffusion in Co4N.

The direct control of the tunneling current as a function of electric polarization in ferroelectric tunnel junctions has recently attracted noticeable attention through the availability of the CMOS compatible ferroelectric hafnium zirconium oxide ( Hf0.5Zr0.5O2). While a lot of progress has been made in the understanding of ferroelectric tunnel junctions, the control and optimization of the volume fraction of the polar orthorhombic phase are still in its infancy and raise the question whether all observed resistive switching events are necessarily associated with polarization reversal. Trap-assisted tunneling is also able to modulate the current density through a field-induced variation of the oxygen vacancy density across the tunnel junction. The amplitude of the effect should depend on the pre-existing density of oxygen vacancies introduced during the fabrication. Here, by controlling the oxygen partial pressure during the RF magnetron sputtering deposition of the non-polar monoclinic phase of Hf0.5Zr0.5O2 thin films of approximately 3 nm, we demonstrate tuning of its transport mechanism due to the formation of oxygen vacancies. We show that two mechanisms dominate the current transport depending on the average distance between traps. For large oxygen content in the Hf0.5Zr0.5O2 thin film, direct tunneling (DT) is the dominant transport mechanism, while the electrical conductivity in the oxide can be described by the phonon-assisted tunneling between traps (PATTs) for the oxygen deficient Hf0.5Zr0.5O2 thin film. We derive a critical inter-trap distance and a critical thickness value that explains the transition from DT to PATT mechanism in Hf0.5Zr0.5O2 thin films.

Conventional permanent magnets that exhibit high-saturation magnetizations and coercivities contain rare earth elements or noble metals, which renders them economically unsustainable. L10-FeNi alloy, which does not contain such elements, possesses excellent magnetic properties even at high temperatures. However, the coercivity of the fabricated alloy is much lower than its potential coercivity. In this study, to investigate the temperature dependence of L10-FeNi and its magnetic properties in the vicinity of the single magnetic domain size, L10-FeNi island structures were fabricated via sputter deposition of a FeNi alloy and subsequent application of the nitrogen insertion and topotactic extraction method. The crystallinity of FeNiN in the islands improved during the nitriding process, whereas in the denitriding process, the isolation of the islands for magnetic decoupling proceeded owing to volume shrinkage during phase transition. The superlattice structures in each process were confirmed based on transmission electron microscopy diffraction patterns. By varying the nominal film thickness, it was found that a 20 nm film containing island structures, which had undergone a complete denitriding reaction and showed particle sizes close to the single magnetic domain size, exhibited the highest coercivity (188 kA/m at 10 K) reported thus far. Even at 600 K, the coercivity was only reduced by 15% compared to that at 300 K. These results suggest that L10-FeNi with a controlled island structure is a promising magnetic material with good heat resistance.

The heteroepitaxy of a single crystal diamond has been carried out in the KTaO3 substrate using Ir as a buffer layer. KTaO3 has a perovskite lattice structure and displays a face-centered cubic structure. Its lattice constant is 3.98 A, which is only 3% mismatched with the lattice constant of Ir of 3.84 A, and also, its thermal expansion coefficient is 4.031 × 10−6/K, which is nearly close to that of diamond 3.85 × 10−6/K (at 1223 K), making it to be regarded as an alternate substrate of the heteroepitaxy of a single crystal diamond. The magnetron sputtering technique was used to deposit Ir thin films with a high orientation in the (001) direction on a KTaO3 (001) substrate. Thereafter, bias enhanced nucleation on Ir surface was grown by direct current chemical vapor deposition (CVD) methods. At last, a single crystal diamond with a size of 10 × 10 × 0.78 mm3 has been grown, whose (004) rocking curve FWHM is 183 arc sec, which testifies to the excellent crystalline quality of the heteroepitaxial diamond film.

Extended data retention is a cardinal impediment for ferroelectric memories and serves a pivotal role for nonvolatile memory applications. Here, nonvolatile Metal–Ferroelectric–Insulator–Semiconductor (MFIS) structures are fabricated by using thin films of Strontium Bismuth Tantalum Oxide (SrBi2Ta2O9) as ferroelectric and high-κ lanthanum oxide (La2O3) as a buffer insulator on p-Si substrates via RF magnetron sputtering. The grazing incidence x-ray diffraction analysis confirms the dominant (111) and (115) ferroelectric perovskite phases of SrBi2Ta2O9 thin films. Albeit, atomic force microscopy surface micrographs revealed highly smooth La2O3 and SBT (SrBi2Ta2O9) thin films with a surface roughness of ∼0.22 ± 0.04 nm and ∼1.05 ± 0.03 nm, respectively. Capacitance–voltage (C–V), capacitance–time (C–T), and current–voltage (I–V) characteristics of Pt/SrBi2Ta2O9/La2O3/Si, MFIS structures, exhibited a high memory window of ∼1.1 V at ±5 V sweep voltage, data retention measured until ∼104 s even on the extrapolation up to 10 years, and a low leakage current density of ∼12.8 μA/cm2 at −1 V and 300 K. Far from it, the probed conduction mechanism is studied for Pt/SrBi2Ta2O9/La2O3/Si MFIS device structures. The optimum nonvolatile memory characteristics are attributed to the high-quality SBT ferroelectric and the buffer layer La2O3/Si interface of the investigated MFIS structure and also assert from the control Pt/SBT/Pt and Pt/La2O3/Si results. Thus, the proposed Pt/SrBi2Ta2O9/La2O3/Si structure is a potential candidate for a gate stack of one-transistor (1T) type Ferroelectric Field-Effect Transistors nonvolatile memory applications.

Spin–orbit torques (SOTs) in compensated ferrimagnets (FMs) have been widely studied due to their abundant advantages for the application in spintronic devices. Recently, the SOT in FM metals near compensation tuned by composition and temperature has been reported. However, the SOT in FM insulators (FMIs) near compensation still remains elusive. In this work, we report the study of the SOT in FMI near compensation tuned by the temperature. First, Pt/Gd3Fe5O12 (GdIG) bilayer films with high crystallinity and perpendicular magnetic anisotropy were fabricated by magnetron sputtering. Then, the SOT was measured by varying the temperature. It is found that the SOT generation is drastically enhanced close to the compensation temperature, which is verified to be caused by the decrease in the net magnetization. The effective spin Hall angle in Pt/GdIG bilayer films is estimated to be ∼0.0073, which is almost independent of the temperature. Our study provides a potential approach in emerging FMIs for spintronic devices with low-energy consumption.

In this study, the Raman biaxial stress coefficients KII and strain-free phonon frequencies ω0 have been determined for the E2 (low), E2 (high), and A1 (LO) phonon modes of aluminum nitride, AlN, using both experimental and theoretical approaches. The E2 (high) mode of AlN is recommended for the residual stress analysis of AlN due to its high sensitivity and the largest signal-to-noise ratio among the studied modes. The E2 (high) Raman biaxial stress coefficient of −3.8 cm−1/GPa and strain-free phonon frequency of 656.68 cm−1 were then applied to perform both macroscopic and microscopic stress mappings. For macroscopic stress evaluation, the spatial variation of residual stress was measured across an AlN-on-Si wafer prepared by sputter deposition. A cross-wafer variation in residual stress of ∼150 MPa was observed regardless of the average stress state of the film. Microscopic stress evaluation was performed on AlN piezoelectric micromachined ultrasonic transducers (pMUTs) with submicrometer spatial resolution. These measurements were used to assess the effect of device fabrication on residual stress distribution in an individual pMUT and the effect of residual stress on the resonance frequency. At ∼20 μm directly outside the outer edge of the pMUT electrode, a large lateral spatial variation in residual stress of ∼100 MPa was measured, highlighting the impact of metallization structures on residual stress in the AlN film.

Sputtered Fe/Nb multilayers were prepared with Nb thicknesses dNb of 35 A and with Fe thicknesses dFe of 35 A and sputtered Fe/Nb/Fe trilayers was deposited with Nb thicknesses dNb in the range 50 A and with Fe thicknesses dFe in the range 120 A, respectively using high power impulse magnetron sputtering technique. X-ray reflectivity (XRR) measured patterns revealed the high quality of the film structure with a low surface and interface roughness. Nb thin films synthesized with Nb thicknesses dNb in the range 150-700 A using conventional direct-current magnetron sputtering (CMS) have been compared with those made by high power impulse magnetron sputtering (HIPIMS) operated at the same average power by means of XRR. The obtained XRR patterns were fitted using the Parratt32 software. It was observed that films grown by HIPIMS method have a higher density and interface roughness than that grown by the CMS method. It was also observed that the deposition rate is increasing with the increase of deposition power; it shows linear behavior with deposition power.