Change In Substrate Temperature Research Articles

Effect of Photolithographic Biomimetic Surface Microstructure on Wettability and Droplet Evaporation Process

In nature, engineering technology and daily life, wetting phenomena are widespread and have essential roles and significance. Bionics is becoming increasingly important nowadays and exploring the mechanism that influences biomimetic surface microstructure on droplet wetting process and heat and mass transfer characteristics is becoming more meaningful. In this paper, based on photolithography technology, SU-8 photoresist was used as raw material to prepare biomimetic surfaces with microstructures in various arrangements. The research results show that the wettability of biomimetic functional surfaces can be regulated by regulating the shape and arrangement of photoresist micro-pillars. At the same time, the effects of surface microstructure configuration and roughness on the heat and mass transfer processes within the droplets were also comprehensively studied. The results show that a biomimetic surface with cylindrical micro-pillars can effectively inhibit the evaporative cooling effect of the liquid–vapour interface. This effect becomes more evident with the increase in roughness, and the interface temperature difference can be reduced by up to 18%. Similarly, the biomimetic surface with cylindrical micro-pillars can also effectively promote the evaporation rate of sessile droplets, which can be increased by about 13%. In addition, the research also shows that regardless of the structure, substrate temperature changes will significantly impact the wetting phenomenon of the biomimetic surface. This study aims to guide the optimal design of biomimetic surfaces prepared based on photoresistance.

Magnetron sputtered silicon thin films for solar cell applications

One of the important directions of research in photovoltaics is the development of new thin-film technology, which can replace the currently used, more expensive bulk silicon technology. The article discusses the findings from research focused on optimizing the parameters for the deposition of silicon thin films with P-type electrical conductivity for applications in photovoltaics. The growth rate was determined depending on the change in substrate temperature using reflectometry and the influence of deposition time on optical properties was determined using UV/VIS spectroscopy. Photovoltaic structures were made on substrates with an ITO layer and their electrical parameters were measured. The authors applied the magnetron sputtering method to deposit the layers, selecting it over the commercially used the chemical vapor deposition (CVD) method. This replacement could alleviate the necessity for high temperatures and broaden the potential applications of thin-film solar cells.

Substrate temperature effect on the structural, morphological and optical properties of pyrolyzed bi-phase Cu2O–CuO thin films

Multiphase nanomaterials are fascinating due to the synergistic effect between the crystalline phases that lead to improved device performance. Publications are available for the synthesis of monophasic copper oxides, such as Cu2O and CuO, and the mixed-phase Cu2O–CuO counterpart using different synthesis methods. However, literature report is scarce that focuses on the fabrication of bi-phase Cu2O–CuO thin films by the spray pyrolysis technique without phase transformation to form the monophasic counterparts. The present work attempts to prepare solely mixed-phase Cu2O–CuO films through small incremental change in substrate temperature, in steps of 20 °C. Structural analysis of the pyrolyzed films revealed the formation of a bi-phase Cu2O–CuO crystal system. The crystallite size increased from 18.64 to 23.94 nm, microstrain decreased from 7.134 ×10−4 to 5.625 ×10−4, while stacking faults decreased from 3.753 ×10−3 to 2.942 ×10−3 with an increase in temperature. Microstructural analysis showed nanoaggregates with increased particle size at increasing temperature. The films exhibited a common optical bandgap of 2.61 eV. The values of the static refractive index and optical electronegativity were found to be 2.47 and 0.70, respectively. The surface roughness increased from 41.3 to 90.9 nm with substrate temperature.

Investigations on temperature dependent properties of spray deposited tin oxide thin films

The present study reported the temperature dependent properties of tin oxide (SnO2) thin films deposited by using conventional, cost effective and non-vacuum-based spray pyrolysis technique (SPT). The as deposited films were characterized by various characterization techniques such as X ray diffraction (XRD), UV-Vis spectroscopy and Scanning electron microscopy (SEM) to study their structural, optical and morphological properties respectively. XRD analysis revealed tetragonal rutile crystal structure of SnO2 with preferred orientation along (200) plane. The refinement of XRD data was also carried out by Rietveld refinement to obtain the fitting parameters, crystallite size and lattice parameters. UV-Vis study showed considerable change in optical absorbance and transmittance with change in substrate temperature. Effect of substrate temperature on film thickness, refractive index and band gap energy were determined by Swanepoel method and by Tauc’s plot respectively. The Urbach energy was also calculated and were correlated to the defects in SnO2 films. SEM micrograph showed the transformation from granules to nanospheres as a function of substrate temperature. Electrical properties were determined by Hall effect measurements which gives carrier concentration, electrical resistivity and mobility in the order of 1019-1020 /cm3, 10−2-10−3 Ω.cm and 4–23 cm2/Vs respectively.

ANALYSIS OF THE DYNAMICS AND FREEZING OF WATER DROPLETS ON METAL SURFACES

This article investigates the effects of substrate temperature, tilt angle, and droplet size on droplet impact dynamics and freezing using a Motionpro high-speed camera and a DSA-30 droplet surface analyzer. The temperature of the substrate was changed from the ambient temperature of 21°C to -13°C, and three droplet sizes (<i>D</i><sub>0</sub> = 2.57, 3.02, and 3.54 mm) were studied. The results show that some air gets trapped under the liquid film during the impact process due to insufficient escape time, resulting in the interior of the droplet being in an unstable state. Simultaneously, due to the low surface energy of the substrate, liquid droplets exhibit a rebound effect upon impact with the ambient temperature substrate, reaching their maximum height and forming a dumbbell-like shape. Furthermore, the rebound height decreases rapidly with the decrease in substrate temperature. A change in substrate temperature had no significant effect on the droplet spreading process, but decreasing substrate temperature increased the viscous forces, thereby suppressing the droplet retraction and oscillation processes, ultimately leading to longer droplet freezing times. Additionally, at low Weber numbers (<i>We </i>< 250), the droplet dimensionless parameters exhibited a similar trend with respect to dimensionless time or temperature.

Substrate heat-assisted spray pyrolysis of crack-free ytterbium sesquioxide-Si heterojunction diodes for photo-sensing applications

A simple spray pyrolysis is used to develop ytterbium sesquioxide (Yb2O3) on aluminoborosilicate glass substrates at variable substrate temperatures. A cubic crystal system grows along the (222) plane as substrate temperature changes from 600 to 700 °C. Dispersed grains become cluster-like particles in film structures as the temperature rises. The Yb2O3 composition purity.is further ensured by energy dispersive x-ray analyses. Structure improves with optical spectrum transparency. The altered crystallite and grain size shifted the bandgap energy to higher wavelengths. Regarding Ag/n-Yb2O3/p-Si/Ag heterojunction diode performance, the barrier height increases from 0.67 to 0.70 as the substrate temperature rises. The film structure at 700 °C exhibited the best results, including an electrical conductivity of 2.503×10–15 S/cm and an activation energy of 0.129 kJ/mol. In addition, the estimated ideality factors (n) are 4.5 and 2.9 under dark and light conditions, respectively.

Influence of the Deposition Rate and Substrate Temperature on the Morphology of Thermally Evaporated Ionic Liquids

The wetting behavior of ionic liquids (ILs) on the mesoscopic scale considerably impacts a wide range of scientific fields and technologies. Particularly under vacuum conditions, these materials exhibit unique characteristics. This work explores the effect of the deposition rate and substrate temperature on the nucleation, droplet formation, and droplet spreading of ILs films obtained by thermal evaporation. Four ILs were studied, encompassing an alkylimidazolium cation (CnC1im) and either bis(trifluoromethylsulfonyl)imide (NTf2) or the triflate (OTf) as the anion. Each IL sample was simultaneously deposited on surfaces of indium tin oxide (ITO) and silver (Ag). The mass flow rate was reproducibly controlled using a Knudsen cell as an evaporation source, and the film morphology (micro- and nanodroplets) was evaluated by scanning electron microscopy (SEM). The wettability of the substrates by the ILs was notably affected by changes in mass flow rate and substrate temperature. Specifically, the results indicated that an increase in the deposition rate and/or substrate temperature intensified the droplet coalescence of [C2C1im][NTf2] and [C2C1im][OTf] on ITO surfaces. Conversely, a smaller impact was observed on the Ag surface due to the strong adhesion between the ILs and the metallic film. Furthermore, modifying the deposition parameters resulted in a noticeable differentiation in the droplet morphology obtained for [C8C1im][NTf2] and [C8C1im][OTf]. Nevertheless, droplets from long-chain ILs deposited on ITO surfaces showed intensified coalescence, regardless of the deposition rate or substrate temperature.

Effect of substrate temperatures on structural, optical and dispersion energy parameters of RF sputtered nickel oxide thin films

Thin films of nickel oxide (NiO) have been widely identified as a promising ion storage layer in electrochromic devices owing to their excellent electrochemical properties. There is, however, a lack of accurate description of their optical parameters, which are quite important to explore the optical and electrochromic characteristics of NiO. In the present investigation, nickel oxide (NiO) thin films have been deposited using radio frequency (RF) magnetron sputtering at different substrate temperatures (Tsub) viz. 100, 200 and 300 °C. The consequences of substrate temperature on the structural, morphological, optical, and vibrational properties were examined. The XRD pattern showed increased crystallinity with an increase in substrate temperature. Surface morphology revealed an ultrafine and smooth morphology. The average optical transmittance varied between 64% and 85%. Shrinkage in the energy bandgap was observed with the change in substrate temperature. The values of optical parameters like refractive index (n), extinction coefficient (k), the real part of the dielectric constant (ε1), the imaginary part of the dielectric constant (ϵ2), and porosity of NiO films were found to change with an increase in substrate temperature. The effect of substrate temperature on dispersion energy parameters (Eo and Ed) derived from the Wemple-DiDomenico model was calculated and discussed in detail. Room temperature photoluminescence studies revealed peaks along 3.39 eV (365 nm) and 2.95 eV (420 nm) nm as a consequence of band-band PL phenomena for nickel oxide and defects. In the Raman spectrum, one predominant peak around 560 cm−1 corresponds to the one-phonon LO mode, and another minor peak at 1100 cm−1 owing to the two-phonon LO mode were observed, which arises from Ni–O vibrations. The observed results reveal the potential application of the NiO films in optoelectronic and electrochromic device applications.

Carbon content, carbon fixation yield and dissolved organic carbon release from diverse marine nitrifiers.

Nitrifying microorganisms, including ammonia-oxidizing archaea, ammonia-oxidizing bacteria, and nitrite-oxidizing bacteria, are the most abundant chemoautotrophs in the ocean and play an important role in the global carbon cycle by fixing dissolved inorganic carbon (DIC) into biomass. The release of organic compounds by these microbes is not well quantified, but may represent an as-yet unaccounted source of dissolved organic carbon (DOC) available to marine food webs. Here, we provide measurements of cellular carbon and nitrogen quotas, DIC fixation yields and DOC release of 10 phylogenetically diverse marine nitrifiers. All investigated strains released DOC during growth, representing on average 5-15% of the fixed DIC. Changes in substrate concentration and temperature did not affect the proportion of fixed DIC released as DOC, but release rates varied between closely related species. Our results also indicate previous studies may have underestimated DIC fixation yields of marine nitrite oxidizers due to partial decoupling of nitrite oxidation from CO2 fixation, and due to lower observed yields in artificial compared to natural seawater medium. The results of this study provide critical values for biogeochemical models of the global carbon cycle, and help to further constrain the implications of nitrification-fueled chemoautotrophy for marine food-web functioning and the biological sequestration of carbon in the ocean.

Influence of the Al-Doped ZnO Sputter-Deposition Temperature on Cu(In,Ga)Se2 Solar Cell Performance.

Heterojunction Cu(In,Ga)Se2 (CIGS) solar cells comprise a substrate/Mo/CIGS/CdS/i-ZnO/ZnO:Al. Here, Al-doped zinc oxide (AZO) films were deposited by magnetron sputtering, and the substrate temperature was optimized for CIGS solar cells with two types of CIGS light absorbers with different material properties fabricated by three-stage co-evaporation and two-step metallization followed by sulfurization after selenization (SAS). The microstructure and optoelectronic properties of the AZO thin films fabricated at different substrate temperatures (150–550 °C) were analyzed along with their effects on the CIGS solar cell performance. X-ray diffraction results confirmed that all the deposited AZO films have a hexagonal wurtzite crystal structure regardless of substrate temperature. The optical and electrical properties of the AZO films improved significantly with increasing substrate temperature. Photovoltaic performances of the two types of CIGS solar cells were influenced by changes in the AZO substrate temperature. For the three-stage co-evaporated CIGS cell, as the sputter-deposition temperature of the AZO layer was raised from 150 °C to 550 °C, the efficiencies of CIGS devices decreased monotonically, which suggests the optimum AZO deposition temperature is 150 °C. In contrast, the cell efficiency of CIGS devices fabricated using the two-step SAS-processed CIGS absorbers improved with increasing the AZO deposition temperature from 150 to 350 °C. However, the rise in AZO deposition temperature to 550 °C decreased the cell efficiency, indicating that the optimum AZO deposition temperature was 350 °C. The findings of this study provide insights for the efficient fabrication of CIGS solar cells considering the correlation between CIGS absorber characteristics and AZO layer deposition temperature.

Reactive Physical Vapor Deposition of Yb-Doped Lead-Free Double Perovskite Cs2AgBiBr6 with 95% Photoluminescence Quantum Yield

Yb-doped Cs2AgBiBr6 is a promising lead-free halide double perovskite that can be used as a downconverting coating on silicon solar cells to redshift UV and blue photons to the near-infrared where the quantum efficiencies are larger. Herein, we show that photoluminescence quantum yield (PLQY) of Yb-doped Cs2AgBiBr6 thin films synthesized via physical vapor deposition depends strongly on how the substrate temperature changes during deposition, which determines the amount of Bi incorporated into the film. Yb-doped Cs2AgBiBr6 films with PLQY as high as 95% were deposited with excess BiBr3 and by ramping substrate temperature during the deposition. Ramping the substrate temperature reduces BiBr3 loss from the film by promoting reactions that form Cs2AgBiBr6. As a result, the films formed have high PLQY and retain 93% of their initial PLQY values after 1 month.

Low-temperature growth of In2O3 films on a-plane sapphire substrates by pulsed laser deposition

High-quality body-centered cubic In2O3 films were grown on a-plane sapphire substrates at a temperature range of 100–600 °C by pulsed laser deposition. The structure, optical, and electrical properties were studied by X-ray diffraction, Raman spectroscopy, spectrophotometer, and Hall effect. The obtained In2O3 films have a bcc structure, a high carrier concentration range of 1 × 1019–9 × 1020 cm−3, a mobility range of 8 to 30 cm2V−1s−1, and a wide bandgap of 3.7–3.9 eV. The change of substrate temperature affects the crystalline quality, transmittance, carrier concentration, mobility, and bandgap value of In2O3 films. We believe that the low-temperature growth of high-quality In2O3 films can make In2O3 more widely used in various semiconductors devices.

Effects of indium composition on the surface morphological and optical properties of InGaN/GaN heterostructures

PurposeThis study aims to investigate the effects of indium composition on surface morphology and optical properties of indium gallium nitride on gallium nitride (InGaN/GaN) heterostructures.Design/methodology/approachThe InGaN/GaN heterostructures were grown on flat sapphire substrates using a metal-organic chemical vapour deposition reactor with a trimethylindium flow rate of 368 sccm. The indium composition of the InGaN epilayers was controlled by applying different substrate temperatures. The surface morphology and topography were observed using field emission scanning electron microscope (F.E.I. Nova NanoSEM 450) and atomic force microscopy (Bruker Dimension Edge) with a scanning area of 10 µm × 10 µm, respectively. The compositional analysis was done by Energy Dispersive X-Ray Analysis. Finally, the ultraviolet-visible (UV-Vis) spectrophotometer (Agilent Technology Cary Series UV-Vis-near-infrared spectrometer) was measured from 200 nm to 1500 nm to investigate the optical properties of the samples.FindingsThe InGaN/GaN thin films have been successfully grown at three different substrate temperatures. The indium composition reduced as the temperature increased. At 760 C, the highest indium composition was obtained, 21.17%. This result was acquired from the simulation fitting of ω−2θ scan on (0002) plane using LEPTOS software by Bruker D8 Discover. The InGaN/GaN shows significantly different surface morphologies and topographies as the indium composition increases. The thickness of InGaN epilayers of the structure was ∼300 nm estimated from the field emission scanning electron microscopy. The energy bandgap of the InGaN was 2.54 eV – 2.79 eV measured by UV-Vis measurements.Originality/valueIt can be seen from this work that changes in substrate temperature can affect the indium composition. From all the results obtained, this work can be helpful towards efficiency improvement in solar cell applications.

A Simple Analysis Method of Specific Anammox Activity Using a Respirometer

Anaerobic ammonium oxidation (anammox) is a biological nitrogen removal process with attractive prospects, such as no carbon addition, less aeration, lower greenhouse gas generation, and lower sludge production. However, it is difficult to maintain a stable anammox process since the anammox bacteria have a slow growth rate and high sensitivity to many factors. Therefore, it is very important to analyze and maintain the anammox activity as a process indicator for its successful operation. The conventional method for measuring the concentration of nitrogen compounds, such as ammonium, nitrite, or nitrogen gas is inconvenient during the reaction time for specific anammox activity (SAA) analysis, which can result in an inaccurately determined SAA due to the substrate loss and temperature change. In this study, a respirometer was utilized to analyze the SAA. The SAA values from a respirometer (rSAA) showed a similar pattern to the SAA values (mSAA) from the conventional method. All of the SAA analyses showed the highest value at 35 °C with a granule size of <1 mm. Statistical analysis showed no significant differences regardless of the analysis method, since the p-values for the t-test and Wilcoxon rank-sum test were >0.05. Therefore, the respirometer can be used as a simple and efficient tool for SAA analysis. Moreover, the operating maintenance and management of the anammox process can be improved due to the simple SAA analysis in the field.

Modeling dynamic characteristics of the thermally affected embedded laminated nanocomposite beam containing multi-scale hybrid reinforcement

The current paper is devoted to investigate the free and forced vibrational responses of the multi-phase angle-ply laminated nanocomposite beam with focusing on the occurrence of resonance phenomenon. The influence of uniform thermal loading and three-parameter Kerr substrate which can affect the resonance behavior of the structure is surveyed. Utilizing a superior nanofiller with the name of Graphene Oxide (GO) together with the macro-scale Carbon Fibers (CFs) will constitute a novel multi-scale hybrid reinforcement for the polymer matrix. The combination of the Halpin–Tsai micromechanical model and extended rule of the mixture is implemented to estimate the effective properties of this multi-scale hybrid nanocomposite. Refined higher-order beam theory is employed to obtain the displacement fields and then with applying Hamilton’s principle, the governing equations are derived and analytically solved via Galerkin's exact solution method. Also, the presented results are validated with reputed works in open literature. Furthermore, some tabulated and graphical results are provided to reveal the effects of various parameters such as fibers’ orientation angle, weight and volume fractions of reinforcements, different boundary conditions, beam’s slenderness ratio, Kerr substrate parameters, excitation frequency and temperature change on the dynamic behavior of the proposed structure.

Numerical simulation of the solidification phenomena of single molten droplets impinging on non-isothermal flat plate using explicit moving particle simulation method

In jet engines and gas turbines, the deposition phenomenon is attributed to the adhesion of molten droplets on walls. In this study, numerical simulations of the deposition phenomena on a substrate were performed using the explicit moving particle simulation (E-MPS) method. We adopted a non-isothermal condition for the substrate using a coupling method including wall particles and a regular grid to estimate the heat conduction to and within the substrate for enhanced numerical accuracy. This coupling method was validated by comparing the theoretical values of the one-dimensional unsteady heat conduction. Simulations were performed to study the solidification phenomena of a single molten stannum (Sn) droplet impinging and solidifying on a vertical substrate. The droplet behavior from impingement to solidification shows reasonable agreement with experimental results in terms of spread factor, taking into account the heat exchange between the droplet and substrate, including the substrate temperature change. Although temperature change in the substrate is limited to areas near the impinging droplet, temperature distributions on the interface differ between the early and later stages. The high-temperature region appears near the impinging center except near the stagnation point for the former stage, while it is near the center for the latter stage. The finger and bump shapes around the impinging droplet are explained via Rayleigh–Taylor and Plateau–Rayleigh instabilities, respectively, using the actual expanding acceleration of the liquid film.

Labile carbon addition alters soil organic carbon mineralization but not its temperature sensitivity in a freshwater marsh of Northeast China

Inland freshwater marshes are notable contributors to soil organic carbon (SOC) pool across the globe. Input of labile C can greatly affect the direction and intensity of priming effects (PE) on SOC decomposition, which will likely be altered under climate warming. However, the effects of temperature on priming of wetland SOC mineralization and its temperature sensitivity (Q10) under varied C inputs remain unclear. We conducted a laboratory incubation experiment with 13C-glucose addition to investigate the effects of labile C on priming and Q10 values of the freshwater wetland SOC decomposition at 10 and 20 °C in Northeast China. Results showed that temperature and glucose additions had significant effects on CO2 efflux rates, but interactive effects were not observed. The positive priming that increased with increasing C added at both temperatures was detected, while the magnitude of priming at 10 °C was higher than that at 20 °C. There were no significant differences in Q10 values under low and high glucose additions, both of which were obviously lower than that of no glucose addition treatment. Total microbial biomass (total PLFAs) at 20 °C was significantly decreased compared to that at 10 °C, while the opposite trend was observed for CO2 efflux at the end of incubation. High glucose addition induced higher PLFAs than other treatments at both temperatures, but the composition of microbial community was not significantly altered by temperature under labile additions. We conclude that substrate availability and temperature change may have great impacts on wetland soil C turnover through priming effects. We highlight that more attention should be paid on the relationship between labile substrates and temperature sensitivity of decomposition under climate warming.

Occurrence of Sharp Hydrogen Effusion Peaks of Hydrogenated Amorphous Silicon Film and Its Connection to Void Structures

The amount of hydrogen released from plasma‐enhanced chemical vapor (PECVD) deposited hydrogenated amorphous silicon (a‐Si:H) layers is determined by gas effusion measurements. A sharp peak (SP) is observed in the effusion spectra of samples with substrate temperature T S ≥ 200 °C. Light microscopic images indicate the formation of bubbles after deposition for all samples and film deterioration after effusion measurement in correlation with the presence of the hydrogen SPs. Change in substrate temperature varies with the microstructure of the film, the hydrogen concentration, and the density. A low T S leads to a porous structure with large number of interface bubbles, and therefore no hydrogen‐induced SP appears during hydrogen effusion. Whereas high T S causes a compact a‐Si:H film in which the hydrogen effusion is limited by the longer diffusion, while the number of interface bubbles decreases. The storage of near substrate hydrogen in the bubbles in compact material leads to a local explosion by increase in excessive pressure. The difference between the low temperature peak and the position of the SP in the effusion spectra indicates the time required to fill the interface bubbles with hydrogen, which decreases with increasing film density, suggesting that the volume of the interface bubble decreases.

Influence of strain on the InAs1 – xSbx composition

The composition of III–V semiconductor alloys with multiple group V elements results from a complex interaction of each group V species with each other and with group IIIs. Molecular beam epitaxy growth conditions, such as the group V absolute fluxes and flux ratios, substrate temperature, group III growth rate, the presence of surfactants, and the alloy's strain state, all affect the composition of InAs1 – xSbx. These factors are codependent in a manner that is far from completely established. In this work, the authors examine how the sign and degree of strain affects the film’s composition. In this study, the authors show that InAs1 – xSbx alloys have some ability to resist the creation of strain by self-adjusting the incorporation of the group V elements that would otherwise be changed in an unfavorable way (by, for example, a substrate temperature change). This self-latching to the substrate lattice constant is beneficial, since it means that the fluxes may not have to be adjusted as precisely as otherwise needed.

Experimental investigation of wettability properties for zirconia based coatings by RF magnetron sputtering

Zirconia (Zirconium oxide) thin films were deposited on silicon and corning glass substrates by physical vapor deposition technique. In this experiment the influence of substrate temperature was investigated. The structural and Wettability properties characterized by X-ray diffraction (XRD), Atomic force microscopy and contact angle measurement system. The zirconia films crystallized in the monoclinic phases with (111) orientation, for different sputtering parameters. Average grain size found to be in range of 10–19 nm for different temperature. Surface roughness increases with change in substrate temperature. The surface energy and contact angle measured by contact angle measuring system, exhibited hydrophobic behaviour of zirconium oxide thin films.