Effect Of Deposition Temperature Research Articles

Structural study of epitaxial NdBa2Cu3O7-x films by laser chemical vapor deposition.

Epitaxial NdBa2Cu3O7−x films were prepared on (100) LaAlO3 single crystal substrates by laser chemical vapor deposition (laser CVD). The effect of deposition temperature on preferred orientation, crystallinity, microstructure, deposition rate of films was investigated. The preferred orientation of the NdBCO films changed from a, c-axis to c-axis, then back to a, c-axis, as the deposition temperature was increased from 993 to 1093 K. The highly c-axis-oriented epitaxial NdBa2Cu3O7−x film with critical transition temperature of 87 K was obtained at Tdep = 1033 K, with the in-plane epitaxial orientation relationship of NdBCO [100]∥LAO [010] and NdBCO [010]∥LAO [001]. The growth orientation varied from a-axis to c-axis as the film thickness increased in the case of the a, c-co-oriented NdBCO film. The contribution of thickness-dependent strain relaxation to preferred orientation of the NdBCO films was also discussed.

Effect of deposition temperature on microstructure, corrosion behavior and adhesion strength of Zn-Mg coatings on mild steel

Zn-Mg alloys are strong candidates for the protective coating materials on steel products due to their excellent corrosion resistance compared to pure Zn. In previous research, sputtered Zn-Mg coatings with a high Mg content (above 27 at.%) exhibited a featureless amorphous structure that improved the corrosion resistance of the coatings. However, these Zn-Mg coatings showed a brittle fracture during deformation, resulting in a decrease in adhesion strength. Accordingly, in the present study, to improve the adhesion strength of Zn-Mg coating, the deposition temperature of the Zn-Mg coatings was controlled and the effects of the deposition temperature on the coating microstructure, corrosion resistance, and adhesion strength of the synthesized coatings were investigated. The results revealed that the deposition temperature significantly affected the microstructure as well as the coating properties. Zn-Mg coatings synthesized below 50 °C showed a featureless amorphous microstructure, while porous crystalline Zn-Mg coatings were synthesized above 100 °C. Even though the corrosion resistance of the Zn-Mg coatings decreased slightly as the deposition temperature increased, all of the Zn-Mg coated steel samples exhibited passivation behavior in the corrosion environment. As the deposition temperature of coating increased above 100 °C, the fracture and detachment phenomena of the Zn-Mg coatings during deformation decreased. These results revealed that the adhesion strength of Zn-Mg coating could be improved by controlling the deposition temperature.

Effect of Atomic Layer Deposition Temperature on the Growth Orientation, Morphology, and Electrical, Optical, and Band-Structural Properties of ZnO and Fluorine-Doped ZnO Thin Films

The deposition temperature has a significant effect on the growth and physicochemical properties of ZnO thin films. However, changes within a low temperature range have not yet been fully investigated. In this study, ZnO and fluorine-doped (F-doped) ZnO (ZnO:F) thin films were synthesized on glass substrates by atomic layer deposition, and the effect of deposition temperature (80–160 °C) on the crystallization behavior and electrical, optical, and band-structural properties of the thin films were analyzed. During deposition, a constant fluorine concentration was maintained in the anionic pulse gas by employing a 200:1 (v/v) mixing ratio of deionized water to hydrofluoric acid. We found that c-axis growth was preferred with ZnO thin films, while a-axis growth was preferred for ZnO:F thin films. An enhancement in the carrier concentration was also observed in both thin films with increase in the deposition temperature. In addition, the optical transmittance of ZnO:F thin films was slightly higher than that ...

Effects of deposition temperature and ammonia flow on metal-organic chemical vapor deposition of hexagonal boron nitride

The use of metal-organic chemical vapor deposition at high temperature is investigated as a means to produce epitaxial hexagonal boron nitride (hBN) at the wafer scale. Several categories of hBN films were found to exist based upon precursor flows and deposition temperature. Low, intermediate, and high NH3 flow regimes were found to lead to fundamentally different deposition behaviors. The low NH3 flow regimes yielded discolored films of boron sub-nitride. The intermediate NH3 flow regime yielded stoichiometric films that could be deposited as thick films. The high NH3 flow regime yielded self-limited deposition with thicknesses limited to a few mono-layers. A Langmuir-Hinshelwood mechanism is proposed to explain the onset of self-limited behavior for the high NH3 flow regime. Photoluminescence characterization determined that the intermediate and high NH3 flow regimes could be further divided into low and high temperature behaviors with a boundary at 1500 °C. Films deposited with both high NH3 flow and high temperature exhibited room temperature free exciton emission at 210 nm and 215.9 nm.

Effects of deposition temperature on the electrical properties of Ti/SiC Schottky barrier diodes

Ti Schottky contacts were deposited on n-type 4H-SiC at different temperatures ranging from 28 oC to 900 oC using a magnetron sputtering deposition system to fabricate Schottky barrier diodes. Post deposition annealing at 500 oC for up to 60 hours in vacuum was carried to further improve the contact properties. Optimum barrier height of 1.13 eV and ideality factor of 1.04 was obtained in contacts deposited at 200 oC and annealed for 60 hours. Under a reverse voltage bias of 400 V, the average leakage current on these set of diodes was 6.6 x 10-8 A. Based on the x-ray diffraction analysis, TiC, Ti5Si3 and Ti3SiC2 were formed at the Ti/SiC interface. These results could be beneficial to improving the performance of 4H-SiC Schottky diodes for high power and high temperature applications.

Cu(In,Ga)Se2 solar cells with In2S3 buffer layer deposited by thermal evaporation

We report on physical vapor deposition of indium sulfide (In2S3) buffer layers and its application to Cu(In,Ga)Se2 (CIGSe) thin film solar cell. The Indium sulfide buffer layers were evaporated onto CIGSe at various substrate temperatures from room temperature (RT) to 350 °C. The effect of deposition temperature of buffer layers on the solar cell device performance were investigated by analyzing temperature dependent current-voltage (J-V-T), external quantum efficiency (EQE) and Raman spectroscopy. The fabricated device showed the highest power conversion efficiency of 6.56% at substrate temperature of 250 °C, which is due to the decreased interface recombination. However, the roll-over in J-V curves was observed for solar cell device having buffer deposited at substrate temperature larger than 250 °C. From the measurement results, the interface defect and roll-over related degradation were found to have limitation on the performance of solar cell device.

Improvement of Power Factor of CoSb3 Thermoelectric Thin Films via Microstructure Optimization

Skutterudite CoSb3 has emerged as one of the most studied candidate materials for thermoelectric applications. In this work, CoSb3 thin films were prepared by radio frequency sputtering, and their microstructure was investigated with emphasis on the effect of target composition and deposition temperature. The goal was to enhance the thermoelectric properties of CoSb3 thin films via microstructure optimization. Results showed that the Sb content of films gradually decreased with increasing deposition temperature. Although the thin films prepared by the target with a Co and Sb element ratio of 1:3.5 approached the ideal stoichiometric ratio, they showed poor thermoelectric properties due to the formation of an additional Sb phase. By contrast, the thin films obtained with insufficient Sb showed a single CoSb3 phase and good thermoelectric properties. The mechanism behind this difference was studied accordingly. The power factor of the thin films was enhanced due to their dense structure and good crystallization.

Fast preparation of (111)‐oriented β‐SiC films without carbon formation by laser chemical vapor deposition from hexamethyldisilane without H2

Abstract(111)‐oriented β‐SiC films were prepared by laser chemical vapor deposition using a diode laser (wavelength: 808 nm) from a single liquid precursor of hexamethyldisilane (Si(CH3)3–Si(CH3)3, HMDS) without H2. The effects of laser power (PL), total pressure (Ptot) and deposition temperature (Tdep) on the microstructure, carbon formation and deposition rate (Rdep) were investigated. β‐SiC films with carbon formation and graphite films were prepared at PL ≥ 170 W and Pto ≥ 1000 Pa, respectively. Carbon formation strongly inhibited the film growth. β‐SiC films without carbon formation were obtained at Ptot = 400‐800 Pa and PL = 130‐170 W. The maximum Rdep was about 50 μm·h−1 at PL = 170 W, Ptot = 600 Pa and Tdep = 1510 K. The investigation of growth mechanism shows that the photolytic of laser played an important role during the depositions.

Preparation of silicon carbide coating by chemical vapor deposition by using hexamethyldisilylamine precursor

Silicon carbide (SiC) coating is deposited on C/C composite substrate for the first time by chemical vapor deposition (CVD) with hexamethyldisilylamine (HMDS, C6H19NSi2) as precursor and N2 as carrier gas in an intermediate deposition temperature range. The effects of deposition temperature on phase constitution, surface morphology and deposition rate of the coating are investigated by using X-ray diffraction (XRD), scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The coating exhibits a β-SiC (3C) phase at 1010°C, 1060°C and 1100°C, coexistence of both α-SiC (2H) and β-SiC (3C) phases at 1130°C and 1180°C, as well as a single β-SiC (3C) phase again at 1220°C. The morphology and microstructure of coating change significantly with deposition temperature. The change of phase constitution and surface morphologies are closely linked to nucleation, growth and defects formation in SiC crystals during CVD process.

Effect of Deposition Temperature on Structural and Optical Properties of Zno Films Based on Tourmaline Substrates

Abstract ZnO nanosheet thin films were obtained by the ultrasonic spray pyrolysis technique (USP) on tourmaline and glass substrates at different deposition temperatures. Structural studies show that ZnO crystals are polycrystalline with hexagonal wurtzite structure. The intensity of the characteristic Raman peak, and the (002) preferential orientation, the degree of crystallinity, the grain size achieved by the XRD results are significantly increased with the elevation of the substrate temperature. SEM images show that the ZnO nanoplates laminate parallel to the substrate and assemble to the flower-like column morphology, and ZnO nano crystals have larger lamellae sizes and wider crystalline columns at higher temperature. UV-Vis measurement confirms the maximum absorption peak of the ZnO films on the tourmalines have more red shifts and stronger intensities than that on the glass substrates, and relatively greater wavelength shifts under higher substrate temperature are also observed.

Effect of deposition temperature on morphological, magnetic and elastic properties of ultrathin Co 49 Pt 51 films

Abstract Morphological, magnetic and elastic properties of 5 nm-thick Co 49 Pt 51 films, sputtered on glass substrates, with 20 nm-thick Ta (seed) and Pt (buffer) layers were studied as function of the deposition temperature T d ranging between room temperature and 350° C. Atomic and magnetic force microscopy, vibrating sample magnetometer and Brillouin light scattering techniques were used to investigate the root mean square (RMS) roughness, the magnetic domain configuration, the coercive field (H c ), the perpendicular magnetic anisotropy (PMA), and the dynamic magnetic and elastic properties of the films with T d . The results show that surface uniformity was enhanced since the RMS roughness decreases with T d while magnetic domains typical of films with high PMA are observed. H c and PMA are found to sensibly increase with T d . The dynamic magnetization behavior is characterized by magnetic modes related with the co-existence of hard and soft magnetic areas within the samples. The elastic properties of the stack were first analyzed by means of a model describing the main variation of the elastic wave frequencies within the frame of weighted average thickness, density, Young’s modulus and Poisson coefficient of all the layers constituting the stacks. However, while H c and PMA keep increasing with T d , a more precise experimental analysis of the mechanical behavior shows that the group velocity starts increasing and finally decreases with T d , suggesting that knowledge of the influence of T d on the mechanical properties of each individual layer composing the stack is required to obtain a more accurate analysis.

Impact of deposition temperature on the properties of SnS thin films grown over silicon substrate—comparative study of structural and optical properties with films grown on glass substrates

Tin sulfide (SnS) thin films were chemically deposited over silicon substrate in a temperature range of 250 °C–400 °C. The effects of deposition temperature on the structural, morphological and optical properties of the films were evaluated. All films present an orthorhombic SnS structure with a preferred orientation along (040). High absorption coefficients (in the range of 105 cm−1) were found for all obtained films with an increase in α value when deposition temperature decreases. Furthermore, the effects of substrate type were investigated based on comparison between the present results and those obtained for SnS films grown under the same deposition conditions but over glass substrate. The results suggest that the formation of SnS films onto glass substrate is faster than onto silicon substrate. It is found that the substrate nature affects the orientation growth of the films and that SnS films deposited onto Si present more defects than those deposited onto glass substrate. The optical transmittance is also restricted by the substrate type, mostly below 1000 nm. The obtained results for SnS films onto silicon suggest their promising integration within optoelectronic devices.

Effects of Deposition Temperature on the Properties of ZnO Films Grown by High Power Impulse Magnetron Sputtering

Effects of Deposition Temperature on the Properties of ZnO Films Grown by High Power Impulse Magnetron Sputtering

Effects of deposition temperatures and substrates on microstructure and optical properties of sputtered CCTO thin film

Calcium copper titanium oxide (CaCu3Ti4O12, CCTO) films of 400nm thickness were deposited on ITO and FTO substrates by radio-frequency (RF) magnetron sputtering at different deposition temperatures (100, 150, 200, and 250°C). The influences of deposition temperatures and substrates on the structural, morphological, and optical properties of CCTO films were systematically investigated by XRD, AFM and UV–visible spectrophotometer. XRD study showed that all the CCTO films have a cubic structure. As the deposition temperature increased to 250°C, the film crystallinity was improved, the crystallite sizes became larger and the films deposited on FTO substrates exhibited better crystalline quality. AFM studies revealed that the surface roughness of the films was increased with increasing deposition temperatures for both substrates. The transmittance spectra of the films were more than 50% transparent in the visible region (500–900nm). It was also observed that the optical transmittance and energy band gaps reduced with increased deposition temperatures for both substrates.

Enhanced Optical Absorption of Ti Thin Film: Coupled Effect of Deposition and Post-deposition Temperatures

In the present work, structural, morphological and optical properties of nanostructured titanium (Ti) thin films have been studied. The Ti thin films were fabricated on glass substrate by direct current (DC) magnetron sputtering at varying deposition and post-deposition temperatures (T DA) ranging from 373 K to 773 K. The microstructure and morphology of the Ti thin films were found to be highly dependent on T DA. The root mean square surface roughness (δ rms) was found to increase with T DA up to 673 K and then decreased at 773 K. The absorption (A) of Ti films has shown a similar trend as roughness with T DA; however, the reflection (R) has shown an opposite trend. Maximum A ~99–86% and minimum R ~1–14% were observed in the spectral range of 300–1100 nm for the sample fabricated at T DA = 673 K, which exhibited the highest δ rms ~193 nm. Due to its excellent absorption, this film may be a potential candidate for photonic applications such as a super-absorber.

Effect of deposition temperature on thermal stabilities of copper–carbon films in barrier-less Cu metallization

Copper-carbon alloy films have been applied in barrier-less Cu metallization as seed layers for improving the thermal stabilities. The effect of the deposition temperature on the microstructure and properties of C-doped Cu films on Si substrates was investigated. The films were prepared by ion beam-assisted deposition at various deposition temperatures by co-sputtering of Cu and graphite targets. No inter-diffusion between Cu and Si was observed in Cu(C) films throughout this experiment, because XRD patterns corresponding to their deep-level reaction product, namely, Cu3Si, were not observed in XRD patterns and EDS results of Cu(C) films. Amorphous carbon layer and SiC layer were found in the interface of Cu(C) as-deposited films when deposition temperature rose to 100°C by TEM, high-resolution image and Fourier transformation pattern. The Cu(C) films deposited at 100°C had the best thermal stabilities and the lowest electrical resistivity of 4.44μWcm after annealing at 400°C for 1h. Cu agglomeration was observed in Cu(C) alloy films with deposition temperatures of 200, 300 and 400°C, and the most serious agglomeration occurred in Cu(C) films deposited at 200°C. Undesired Cu agglomeration resulted in a sharp increase in the resistivity after annealing at 300°C for 1h. The deposition temperature of 100°C reflected the superior thermal stabilities of Cu(C) seed layers compared with those of other layers.

A Process Study of Organic/Inorganic Film Materials Deposited by ICP-PECVD at Low Temperature

The film package of organic device plays an important part in organic electronics manufacturing. In order to get high efficiency encapsulation film material, we developed a set of inductively coupled plasma chemical vapor deposition system (ICP-PECVD). A process study on Organic/inorganic hybrid material deposition was carried out for permeation barrier application. In the study, the effects of plasma power, bias power and deposition temperature on film properties were investigated. Fourier transform infrared spectrometry (FTIR), ellipsometer and transmission electron microscopy (TEM) were used to characterize the film properties. The increase of ICP power is favor to SiOx growth with limits. Bias power increases deposition rate. Film density will increase with the rise of deposition temperature. It was found that the ratio of O2/HMDSO flow rate was the key factor to obtain organic layer or inorganic layer. Since the ratio of O2/HMDSO flow rate increase to 10:1, HMDSO will be completely oxidized and Si-O-Si bonds are formed. As the result, the organic film can be obtained with the no oxygen deposition process. Hybrid film between organic film and inorganic film can be deposited under the condition of O2/HMDSO gas flow ratio less than 10:1. Water vapor transmission rates (WVRT) of organic film, inorganic film and organic/inorganic stacks are also tested. The experimental results show that the inorganic thin film has good performance in water or oxygen permeation; organic thin film is mainly for flexibility and inorganic film growth stress release. And interfacial characteristics between inorganic film and organic film have influence on water and oxygen barrier. As result, we obtained the single inorganic film with WVRT of 4.3×10-2g/m2day and the four cycles organic / inorganic alternating structure film with WVRT of 3.66×10-4g/m2 day.

Optical and structural properties of nanostructured copper oxide thin films as solar selective coating prepared by spray pyrolysis method

AbstractCopper (II) oxide thin films were prepared by spray pyrolysis method on soda-lime glass substrates using copper acetate precursor solution. Influence of substrate temperature on structural and optical properties was investigated. Structural analysis of these layers were carried out by X-ray diffraction (XRD). Single phase nature and high crystallinity of CuO nanostructures were observed on XRD patterns. The general appearance of the films was uniform and black in color. FT-IR transmittance spectra confirmed the results from the XRD study. Selective solar absorber coatings of copper oxide (CuO) on stainless steel substrates was prepared by spray pyrolysis method. Effect of deposition temperature on optical properties of thin films was investigated. Optical parameters, absorbance (α) and emittance (α) were evaluated from reflectance data. It can be deduced that the porous structure, such as a light traps, can greatly enhance absorbance, while the composition, thickness and roughness of thin films can greatly influence the emissivity. Single phase nature and high crystallinity of CuO nanostructures were observed by XRD patterns. Solar absorbance of thin films were in the range of 85 % to 92 %.

Effect of deposition temperature on structural, optical and electrical properties of copper bismuth sulphide (CuBiS2) thin films deposited by chemical bath deposition

Abstract The effect of deposition temperature on the structural, optical and electrical properties of copper bismuth sulphide (CuBiS2) thin films deposited by chemical bath deposition onto glass substrates at different deposition temperatures (40 °C, 50 °C, 60 °C and 70 °C) for 5 hours deposition time period was investigated. The obtained films were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), energy dispersive X-ray analysis (EDAX) and optical absorption spectra. All deposited films were polycrystalline and had an orthorhombic structure. Their grain size had changed with deposition temperature and their compositions were nearly stoichiometric. The optical band gap value was decreased from 2.44 eV to 2.33 eV with increasing the film thickness. Electrical parameters such as mobility and type of electrical conduction were determined from the Hall effect measurements. They showed that the obtained films have n-type conductivity and mobility values of the copper bismuth sulphide (CuBiS2) films have changed with deposition temperature.

Effect of Deposition Temperature on the Microstructure and Performance of Vacuum Cold Sprayed Nano-Structured LSCF Cathodes for Solid Oxide Fuel Cells

Here, we investigate the feasibility of using vacuum cold spray process as a novel method for the cost effective fabrication of a nano-structured La0.4Sr0.6Co0.2Fe0.8O3 (LSCF) as a high-performance cathode for low-temperature solid oxide fuel cells (LT-SOFCs). Nano sized LSCF particles were used as feedstock. The effects of deposition temperature and particle size on the phase composition, microstructure, and electrochemical performance of the resulting cathodes were studied. The results indicate that 10~20 μm nano-structured porous LSCF cathodes can be successfully prepared by vacuum cold spray process. However, the deposition temperature shows significant influence on the microstructure. When the cathode was deposited at room temperature, there were many unbonded interfaces between the cathode and electrolyte. With the increase of deposition temperature, the interface bonding was improved. At a deposition temperature of 300 °C, it can be found that the cathode and electrolyte were bonded well. Besides, the results indicate that the cathode polarization resistance decreased significantly with the decrease of spray particle size. When particle size decreased from 150 nm to 50 nm, the cathode polarization resistance decreased from 11 Ωcm2 to 1.5 Ωcm 2 at 450 °C. Our results suggest that vacuum cold spray has potential to be a low-cost and flexible process suitable for the fabrication of nano-structured cathodes for LT-SOFCs.