Influence Of Substrate Temperature Research Articles

Nanoindentation and Photoluminescence Studies of Hydrogenated Boron Carbon Nitride Thin Films

Nanoindentation and photoluminescence (PL) studies were performed on hydrogenated boron carbon nitride thin films deposited using radio frequency magnetron sputtering. Dual target sputtering from B4C and BN targets was used to deposit films. The variation in the composition of films was studied using energy-dispersive X-ray spectroscopy. The influence of hydrogen gas and substrate temperature on the mechanical properties was investigated using nanoindentation measurements. Photoluminescence studies were performed on films deposited under varying hydrogen content and different deposition temperatures. The films deposited in this study exhibited hardness of 6–22 GPa and Young’s modulus of 125–140 GPa. PL spectra demonstrated two prominent emission peaks around 499 nm and 602 nm for the deposited films. Increasing the hydrogen gas ratio in the films induced PL peak shifts to longer wavelengths. Emission spectra shifted to long wavelength with increasing substrate temperature. The emission peak position shifted from 499 nm to 544 nm and from 602 nm to 655 nm as a function of substrate temperature. For the first time, BCNH based thin films PL behavior at low temperature (77 K) has been characterized in this study. The BCNH thin films show a rare phenomenon of negative thermal quenching of emission.

Influences of substrate temperature on the structural, optical and electrical properties of ZnS/Au/ZnS multilayer films

ZnS/Au/ZnS (ZAZ) films which are nano-multilayer and transparent conductive films, were fabricated on quartz substrates at different substrate temperatures via pulsed laser deposition, and the influences of substrate temperature on the structural and optoelectrical characteristics of ZAZ films were researched. X-ray diffraction (XRD) diagrams show that the crystallinity and the quality of the films are improved at higher substrate temperatures, and scanning electron microscope (SEM) show that the film’s surface becomes dense and rough. The substrate temperature also seriously affects the optoelectronic characteristics of ZAZ films. When the substrate temperature is increased, the figure of merit for the ZAZ films decreases. When substrate temperature is 20 ℃, the ZAZ film has the largest figure of merit value (3.34 × 10–3 Ω−1), with an average transmission of 81% in the visible region and a carrier concentration of 1.91 × 1021 cm−3. Transparent, conducting ZAZ films have great potential applications in high-performance optoelectronic devices.

Influence of substrate temperature on the growth properties of Ag-doped SnS films deposited by sputtering method

The Ag-doped SnS films were obtained using a sputtering technique through a sub-sequential layer-by-layer SnS–Ag–SnS–Ag… approach. The structural, optical, and electrical properties of these films deposited at 200 °C, 250 °C, 300 °C, and 350 °C were investigated at a constant Ag concentration of ∼2 at. %. The XRD, Raman, and TEM confirmed that all the diffraction planes of the Ag-doped films belonged only to the orthorhombic crystal phase of the SnS. Based on the reduction in the crystal volume and the compressive type of micro-strain, it confirmed the substitutional doping of Ag into the Sn-vacancy sites in the SnS lattice. The SIMS analysis revealed that the Ag doping into SnS has occurred through the diffusion process with an increase in Ts. The XPS analysis confirmed the presence of the Sn2+, S2−, and Ag2+ oxidation states in the Ag-doped SnS films deposited at 200 °C. The direct optical band bap decreased from 1.44 to 1.42 eV with Ag doping at 200 °C, then it increased to 1.50 eV with rise in Ts (200–350 °C). All the undoped and Ag-doped SnS films exhibited a p-type conductivity. The hole carrier concentration increased from 6.65 × 1015 cm−3 to 5.74 × 1016 cm−3 with Ag doping at 200 °C, later it increased to 1.40 × 1017 cm−3 with an increase of Ts. While the hole mobility increased from 0.34 to 7.81 cm2/V.s with Ag doping at 200 °C, then as Ts increased to 350 °C it decreased to 0.35 cm2/V.s. Finally, the Ag-doped SnS grown at 200 °C exhibited the lowest resistivity (597 Ω cm) than the undoped SnS (2771 Ω cm). The Ag-doped SnS grown at 200 °C is suitable to be used as an efficient solar material.

Influence of in-flight particle characteristics and substrate temperature on the formation mechanisms of hypereutectic Al-Si-Cu coatings prepared by supersonic atmospheric plasma spraying

Hypereutectic Al-Si-Cu coatings were prepared by supersonic atmospheric plasma spraying to enhance the surface performance of lightweight alloys. To find out optimum process conditions and achieve desirable coatings, this work focuses on the influence of three important parameters (in-flight particle temperature, impact velocity, and substrate temperature) on the collected splats morphology, coatings microstructure and microhardness. Results show that appropriate combinations of temperature and velocity of in-flight particles cannot only completely melt hypereutectic Al-Si-Cu particles, especially the primary Si phase, but also provide the particles with sufficient kinetic energy. Thus, the optimized coating consists of 98.6 % of fully-melted region with nanosized coupled eutectic and 0.9 % of porosity. Increasing the substrate deposition temperature promotes the transition from inhomogeneous banded microstructure to homogeneous equiaxed microstructure with a lower porosity level. The observations are further interpreted by a newly developed phase-change heat transfer model on quantitatively revealing the solidification and remelting behaviors of several splats deposited on substrate. Besides, phase evolutions including the formation of supersaturated α-Al matrix solid solution, growth of Si and Al2Cu phases at different process conditions are elaborated. An ideal microstructure (low fractions of unmelted/partially-melted regions and defects) together with solid solution, grain refinement, and second phase strengthening effects contributes to the enhanced microhardness of coating. This integrated study not only provides a framework for optimizing Al-Si based coatings via thermal spraying but also gives valuable insights into the formation mechanisms of this class of coating materials.

Effect of substrate temperature on the deposited thin film CdZnTe transistor

CdZnTe thin film transistor (TFT) detector was deposited on Si/SiO 2 substrate by radio frequency (RF) magnetron sputtering technique. The influence of substrate temperature on the structure of CdZnTe film and the performance of CdZnTe TFT detector were studied. The sputtered CdZnTe films have a multiphase structure consisting of the CdZnTe phase, ZnTe phase and Te phase. (IDS–VDS) characteristics and photosensitivity of CdZnTe TFT detectors at different substrate temperature were reported. When the substrate temperature was 200 °C off-current in CdZnTe TFT detector achieved minimum value of 1.9×10−11 A, as well as a higher photosensitivity of 1.9×103 (obtained at VGS=28.5 V). The optimal condition for preparing CdZnTe TFT detector was the substrate temperature of 200 °C.

Structural properties and surface oxidation states of sputter‐deposited TiO2−x thin films

Titanium dioxide (TiO2−x) films were deposited on silicon (100) substrates from pure titanium (Ti) targets using direct current magnetron sputtering technique. TiO2−x thin films were grown in the thickness range of 515–672 Å with varying sputter powers of 75 and 100 W, at both room temperature (RT) and 200°C substrate temperature (Ts). Structural and compositional characterization of the films, which included surface morphology and study of surface chemical states, was performed. The influences of sputter power and substrate temperature on these parameters were specifically analyzed. Grazing incidence X‐ray diffraction showed that the thin films were amorphous at RT and crystallinity could be achieved only at Ts. The latter showed anatase phase at sputter power of 75 W and transformed into anatase–rutile mixed phase at 100 W. The thickness, roughness, and mass density of the thin films were measured using X‐ray reflectivity. It was observed that for Ts films, the roughness and mass density increased with higher sputter power. Field emission scanning electron microscopy and atomic force microscopy also corroborated this surface roughness result. It was observed from X‐ray photoelectron spectroscopy that the core levels of Ti‐2p3/2 and O‐1s and their corresponding binding energies indicated that only one of the Ti oxidation states, i.e., Ti4+, existed in the films. This work provides insight about the growth of TiO2−x thin films influenced by Ts deposition and different sputter power.

Influence of Substrate Temperature on Electrical and Optical Properties of Hydrogenated Boron Carbide Thin Films Deposited by RF Sputtering

Amorphous hydrogenated boron carbide films were deposited on silicon and glass substrates using radio frequency sputtering. The substrate temperature was varied from room temperature to 300 °C. The substrate temperature during deposition was found to have significant effects on the electrical and optical properties of the deposited films. X-ray photoelectron spectroscopy (XPS) revealed an increase in sp2-bonded carbon in the films with increasing substrate temperature. Reflection electron energy loss spectroscopy (REELS) was performed in order to detect the presence of hydrogen in the films. Metal-insulator-metal (MIM) structure was developed using Al and hydrogenated boron carbide to measure dielectric value and resistivity. Deposited films exhibited lower dielectric values than pure boron carbide films. With higher substrate deposition temperature, a decreasing trend in dielectric value and resistivity of the films was observed. For different substrate temperatures, the dielectric value of films ranged from 6.5–3.5, and optical bandgap values were between 2.25–2.6 eV.

Nanopore-Mediated Spontaneous Dilution of Droplets: When Evaporation Turns to a Dilutor.

Droplet evaporation on surfaces is ubiquitous and affects areas as diverse as climate, microbiology, the chemical industry, and materials science. While solute concentration is the universally taken-for-granted behavior in drop evaporation, the present work shows that saline droplets evaporating on nanoporous thin-film surfaces can get diluted rather than concentrated. The driving mechanism of this phenomenon is attributed to the flow drawn from the drop through the nanopores by an annular peripheral evaporation. This fluid transport can continuously collect the salt solution from a concentrated region of the droplet, which is induced by radial microflows during drop evaporation. The coupling of these processes leads to the overall drop dilution effect. The influence of substrate temperature and drop volume was also investigated. This study opens up new perspectives on many natural phenomena and offers alternatives for physicochemical applications in small dimensions as well as for water desalination technologies.

Strong texture tuning along different crystalline directions in glass-supported CeO2 thin films by ultrasonic spray pyrolysis

The strong facet-dependent performance of glass-supported CeO2 thin films in different applications (catalysis, smart windows, etc.) has been the target of diverse fundamental and technological approaches. However, the design of accurate, cost-effective and scalable methods with the potential for large-area coverage that produce highly textured glass-supported CeO2 thin films remains a technological challenge. In the present work, it is demonstrated that under proper tuning conditions, the ultrasonic spray pyrolysis technique enables one to obtain glass-supported polycrystalline CeO2 films with noticeable texture along both the (100) and (111) directions, as well as with randomly oriented crystallites (no texture). The influence of flow rates, solution molarity, and substrate temperature on the texture and morphological characteristics, as well as optical absorption and Raman response of the deposited films, is evaluated. The obtained results are discussed on the basis of the combined dependence of the CeO2-exposed surfaces on the thermodynamic stability of the corresponding facets and the reaction kinetics, which modulate the crystallite growth direction.

Influence of substrate temperature on the detection sensitivity of surface-enhanced LIBS for analysis of heavy metal elements in water

The influence of substrate temperature on the detection sensitivity of surface-enhanced (SE) LIBS for analysis of heavy metal elements in water is investigated; increasing the substrate temperature can improve the detection sensitivity of SE-LIBS.

Influence of Substrate Temperature on Properties of ZnSe Thin Films Deposited by Electron-beam Evaporation

Influence of Substrate Temperature on Properties of ZnSe Thin Films Deposited by Electron-beam Evaporation

Influence of Substrate Temperature and Magnesium Content on Morphology Evolution and Luminescence of Mg-doped ZnO Films

Influence of Substrate Temperature and Magnesium Content on Morphology Evolution and Luminescence of Mg-doped ZnO Films

F and Al co-doped zinc oxide thin films deposited by ultrasonic spray pyrolysis: Effects of substrate temperature on physical properties

In this study, F and Al co-doped ZnO (FAZO) films were prepared by ultrasonic spray pyrolysis combined with rapid thermal annealing treatment. The influence of substrate temperature (Ts) on the structure, morphology, and electrical and optical properties of the prepared FAZO films was systematically studied. The results showed the hexagonal wurtzite structure of all prepared FAZO films and the gradual changes in the preferred orientation of the films from (100) to (100) and (002) with increasing temperature. With increasing Ts, the diffraction peak of (002) became stronger, the morphology of the thin film changed from a mix of “rice-granular” small particles and “shell-like” large particles to flat and dense morphology, and the root-mean-square variation of the film’s particle size decreased. Furthermore, the resistivity decreased with an increase in Ts, and the film transmittance and optical bandgap increased significantly. The FAZO film prepared at 480 °C had the best photoelectric characteristics, with mobility of 22.9 cm2/(Vs), carrier concentration of 1.75 × 1020 cm–3, resistivity of 1.56 × 10–3 Ωcm, and over 85% average transmittance in the optical range of 400–1400 nm.

The influence of substrate temperature on the near-infrared absorption and carrier mobility of lead phthalocyanine phototransistors

To improve their near-infrared photosensitive properties, lead phthalocyanine (PbPc) phototransistors were fabricated at different substrate temperatures (Ts) of 60, 100, 140 and 180 °C in this paper. The crystal structure, absorption spectra and surface topography of PbPc films were tested. And the photosensitive properties of the devices were measured, the results showed that the photoresponsivity (R), maximum photo/dark current ratio (Pmax) and specific detectivity (D⁎) of the devices first increase and then decrease with Ts increasing and the optimum performances for R, Pmax and D⁎ are acquired at Ts = 100 °C. The relations among substrate temperature, film properties and device performance were studied, which indicated that the phase structure, crystallinity, interconnection of grains, carrier mobility and near-infrared absorption of the PbPc films can be altered via substrate heating, and thus giving rise to the changes in device performance. In addition, a mathematic model that semi-quantitatively describes the relationships of photocurrent versus photoabsorption coefficient and carrier mobility was established.

Phosphorus Catalytic Doping on Intrinsic Silicon Thin Films for the Application in Silicon Heterojunction Solar Cells.

Parasitic absorption and limited fill factor (FF) brought in by the use of amorphous silicon layers are efficiency-limiting challenges for the silicon heterojunction (SHJ) solar cells. In this work, postdeposition phosphorus (P) catalytic doping (Cat-doping) on intrinsic amorphous silicon (a-Si:H(i)) at a low substrate temperature was carried out and a P concentration of up to 6 × 1021 cm-3 was reached. The influences of filament temperature, substrate temperature, and processing pressure on the P profiles were systemically studied by secondary-ion mass spectrometry. By replacing the a-Si:H(n+er with P Cat-doping of an a-Si:H(i) layer, the passivation quality was improved, reaching an iVOC of 741 mV, while the parasitic absorption was reduced, leading to an increase in JSC by ∼1 mA/cm2. On the other hand, the open-circuit voltage and the FF of a conventional SHJ solar cell (with the a-Si:H(n) layer) can be improved by adding a Cat-doping process on the a-Si:H(i) layer, resulting in an increase in FF by 4.7%abs and in efficiency by 1.5%abs.

Influences of Substrate Temperatures and Oxygen Partial Pressures on the Crystal Structure, Morphology and Luminescence Properties of Pulsed Laser Deposited Bi2O3:Ho3+ Thin Films

Monoclinic Bi2O3:Ho3+ powder was synthesized using a co-precipitation method, followed by the deposition of Bi2O3:Ho3+ thin films on Si (100) substrates at various substrate temperatures (room temperature–600 °C) and oxygen partial pressures (5–200 mT) using pulsed-laser deposition. X-ray diffraction analysis showed a single α-Bi2O3 phase at temperatures of 400 and 500 °C, while a mixed α- and β-Bi2O3 phase was obtained at 600 °C. The films deposited at the different oxygen partial pressures showed an α-Bi2O3 and non-stoichiometric phase. The influences of different substrate temperatures and oxygen partial pressures on the morphology and the thickness of the films were analyzed using a scanning electron microscope. The root mean square roughnesses of the films were determined by using an atomic force microscope. The surface components, oxidation states and oxygen vacancies in all the deposited thin films were identified by X-ray photoelectron spectroscopy. The optical band gap of the Bi2O3:Ho3+ thin films was calculated using diffused reflectance spectra and was found to vary between 2.89 and 2.18 eV for the deposited films at the different temperatures, whereas the different oxygen partial pressures showed a band gap variation between 2.97 and 2.47 eV. Photoluminescence revealed that Ho3+ was the emitting centre in the isolated thin films with the 5F4/5S2 → 5I8 transition as the most intense emission in the green region.

Influence of substrate temperature on the energy storage properties of bismuth magnesian niobium thin films prepared by magnetron sputtering

Bismuth magnesian niobium (Bi2Mg2/3Nb4/3O7, BMNO) thin films are deposited on Pt/Ti/SiO2/Si substrates at different substrate temperatures by magnetron sputtering. The effect of substrate temperature on the energy storage properties of BMNO thin films is investigated systematically. The X-ray diffraction pattern reveals the thin films are polycrystalline with cubic pyrochlore structure. The dielectric constant of BMNO thin films increases with the substrate temperature, reaches the maximum value of 161 at 700 °C and starts decreasing thereafter. The maximum electrical breakdown strength and recoverable stored energy density are respectively obtained as 3.78 MV/cm and 58.9 J/cm3 when the BMNO thin films are deposited at 700 °C. In addition, the BMNO thin films possess excellent thermal stability of stored energy properties in a wide range of temperatures (-150 °C–200 °C). These results suggest that the BMNO thin films are a promising candidate for lead-free energy storage application in equipment operation under adverse environments.

Influences of substrate temperatures on etch rates of PECVD-SiN thin films with a CF4/H2 plasma

The dependence of substrate temperatures (50 to −20 °C) on etch rate in two kinds of PECVD SiN films were investigated by a CF4/H2 mixture plasma. The XRR and XPS results indicate that the chemical composition and film density were almost identical for the films. The FTIR shows that the ratio of NH and SiH groups were found to be significantly different in the SiN films. The NH rich films exhibited a lower etch rate at −20 °C than that observed at room temperature or higher, whereas the SiH rich films showed a higher etch rate at −20 °C. We found that the fluorocarbon thickness was thicker in the SiH rich samples than NH rich samples. The fact suggests that hydrogen originated from the broken SiH bonds enhanced the polymerization, which causes the decrease of etch rate. A thinner fluorocarbon thickness was found in the SiH rich samples at low temperature, which results in the higher etch rate. Angular-resolved XPS indicates that NH bonding formed easier on film surface at −20 °C. These results indicate that the bonding structure and substrate temperature affected the fluorocarbon thickness, fluorine reaction probability and hydrogen dissociation during the SiN etching.

Thermal History Induced Surface Restructuring of La0.6Sr0.4CoO3-δ thin-Film Solid Oxide Electrodes and Its Significance for the Catalytic Activity and Stability

Thin-films deposited by Pulsed Laser Deposition (PLD) have enabled the fabrication of cathodes for solid oxide cells (SOC) to possess various microstructures, crystalline states and surface chemistry. These films are often subjected to various processing and thermal treatments which influence the chemical activity and stability of the films. Here, we investigate how the catalytic activity and stability is affected by the thermally induced surface restructuring in complex transition metal oxides, in particular, La0.6Sr0.4CoO3-δ (LSC) thin films grown by PLD.(1) To this end, the influence of substrate temperature during PLD as well as post-annealing treatments on the film microstructure and surface chemistry were studied. In comparison to high-temperature grown films, the post-annealed low-temperature grown films showed 2-fold lower degradation rate in the long-term electrochemical tests at 500 °C. The differences in the electrochemical stability were found to be related to the initial microstructure and morphology of the films (Fig 1). The post-annealed low-temperature grown film showed localised Sr-segregation into protruding particles, leaving the remaining surface with catalytically active stoichiometry. On the other hand, the high-temperature grown films showed a fully covered surface with Sr-rich particles, which continued to thicken with time. Here we emphasise the importance of processing and thermal history in the elemental surface distribution, especially for the stability of LSC64 electrodes and propose that it should be considered as among the main pillars in the design of the active surface.Fig. 1 Top-view (a,d,g) and cross-section view (b,e,h) SEM micrographs and corresponding AFM images (c,f,i) showing the topography of LSC64 films deposited by the PLD: (a−c) LT-grown film, (d−f) postannealed LT-grown film, and (g−i) HT-grown film. (https://pubs.acs.org/doi/10.1021/acsami.0c08308) Reprinted with the permission of the American Chemical Society. Further permissions related to the material excerpted should be directed to the ACS.(1) Celikbilek, O.; Cavallaro, A.; Kerherve, G.; Fearn, S.; Chaix-Pluchery, O.; Aguadero, A.; Kilner, J. A.; Skinner, S. J.. ACS Appl. Mater. Interfaces 2020, 12, 34388−34401. Figure 1

Influence of substrate temperature on microstructural and mechanical properties of 316L stainless steel consolidated by laser powder bed fusion

This study investigates the microstructure and mechanical properties of 316L stainless steel (316LSS) samples fabricated by additive manufacturing (AM), in order to optimise the process for improving the properties of 316LSS parts built by laser powder bed fusion (LPBF). Accordingly, a substrate heating was performed on an SLM 280HL printer fitted with an experimental heating device. During the process, samples are built on a substrate heated up to 600 ∘C. The substrate temperature significantly influences the microstructural evolution and mechanical properties of manufactured parts. Concerning tensile properties, the ultimate tensile strength (UTS) and yield strength (YS) decrease as a function of the substrate temperature whereas the elongation (El) increases as a function of the substrate temperature. These results are similar to those obtained with a post-heat treatment performed on parts manufactured by forging or LPBF. The tensile and impact energies reach values higher than the minimum requirement for 316LSS manufactured by forging, according to the RCC-MRx code used for materials dedicated to French nuclear applications. When the substrate temperature is equal to 350 ∘C, the UTS, YS, El and impact energy reached 596 ± 5 MPa, 489 ± 3 MPa, 48 ± 3% and 123 ± 20 J, respectively. Finally, this study demonstrates that heating the substrate during the process is a promising solution to optimise the fabrication route by suppressing post-process heat treatment of 316LSS made by LPBF.