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Hetero-Orientation Epitaxial Growth of TiO2 Splats on Polycrystalline TiO2 Substrate
摘要： In the present study, the effect of titania (TiO2) substrate grain size and orientation on the epitaxial growth of TiO2 splat was investigated. Interestingly, the splat presented comparable grain size with that of substrate, indicating the hereditary feature of grain size. In addition, hetero- and homo-orientation epitaxial growth was observed at deposition temperatures below 400 °C and above 500 °C, respectively. The preferential growth of high-energy (001) face was also observed at low deposition temperatures (≤ 400 °C), which was found to result from dynamic nonequilibrium effect during the thermal spray deposition. Moreover, thermal spray deposition paves the way for a new approach to prepare high-energy (001) facets of TiO2 crystals.
关键词： hetero-orientation epitaxial growth,preferential growth,crystal morphology,homo-orientation epitaxial growth,deposition temperature,hereditary feature
更新于2025-09-23 15:22:29
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Angstrom Thick ZnO Passivation Layer to Improve the Photoelectrochemical Water Splitting Performance of a TiO2 Nanowire Photoanode: The Role of Deposition Temperature
摘要： In this paper, we demonstrate that angstrom thick single atomic layer deposited (ALD) ZnO passivation can significantly improve the photoelectrochemical (PEC) activity of hydrothermally grown TiO2 NWs. It is found that this ultrathin ZnO coating can passivate the TiO2 surface defect states without hampering the carrier’s transfer dynamics. Moreover, a substantial improvement can be acquired by changing the deposition temperature of the ZnO layer (80 °C, and 250 °C) and named as 80 °C TiO2-ZnO, and 250 °C TiO2-ZnO. It was found that the deposition of this single layer in lower temperatures can lead to higher PEC activity compared to that deposited in higher ones. As a result of our PEC characterizations, it is proved that photoconversion efficiency of bare TiO2 NWs can be improved by a factor of 1.5 upon coating it with a single ZnO layer at 80 °C. Moreover, considering the fact that this layer is a passivating coating rather than a continuous layer, it also keeps the PEC stability of the design while this feature cannot be obtained in a thick shell layer case. This paper proposes a bottom up approach to control the electron transfer dynamics in a heterojunction design and it can be applied to other metal oxide combinations.
关键词： deposition temperature,atomic layer deposition,photoelectrochemical water splitting,ZnO passivation,TiO2 nanowire
更新于2025-09-23 15:21:01
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Controlled optoelectronic properties and abrupt change in photosensitivity by suppressing density of oxygen vacancies in SnO <sub/>2</sub> nanocrystalline thin films prepared at various spray-deposition temperatures
摘要： Nanostructured SnO2 thin films were synthesized at various substrate temperatures using a modified chemical spray pyrolysis (MCSP) technique. The x-ray diffraction (XRD) patterns confirmed the presence of a rutile SnO2 with tetragonal structure for all the resultant film samples. The XRD results ascertained increase in the grain growth rate and consequent enhancement in crystallinity with increasing the spray-deposition temperature. The optical spectroscopic analysis revealed a significant increase in the optical transmission within the visible region as well as a considerable increase in the optical bandgap by increasing the deposition temperature. However, the spectral distribution of the absorption coefficient ascertained the dominance of direct allowed transition for the SnO2 film samples. The analysis of the current-voltage characteristic curves revealed that the variation of the spray-deposition temperature strongly influences the photosensitivity of the film samples. Based on the electrical results, these film samples reveal a semiconductor behaviour of the transport property over the entire investigated range of the working temperature, with two different conduction mechanisms. The optical and electrical results were combined to evaluate the influence of varying the deposition temperature on the figure of merit (FOM) factor for the SnO2 film samples.
关键词： MCSP technique,optical spectroscopic analysis,electrical transport properties,figure of merit,structural properties,spray deposition temperature
更新于2025-09-23 15:19:57
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Studying the influence of deposition temperature and nitrogen contents on the structural, optical, and electrical properties of N-doped SnO2 films prepared by direct current magnetron sputtering
摘要： This report focuses on studying and investigating in detail the structural, electrical, and optical properties of p-type N-doped SnO2 (NTO) versus the deposition temperature and nitrogen content. P-type transparent conductive NTO films were deposited on quartz glass substrates using a direct current (DC) magnetron sputtering method. The substitution of oxygen by nitrogen in the SnO2 host lattice was verified using measurements such as X-ray photoelectron spectroscopy. The position of the N3? defect state in the band gap was determined using photoluminescence and ultra-violet-visible spectroscopy measurements. The data for the (110) to (101) rutile lattice planes changed, and the rutile (plane (101)) to cubic (plane (111)) SnO2 phase transition indicated the substitution of oxygen by nitrogen in the SnO2 host lattice. The best p-type conductive properties achieved were 8 × 10?2 Ω cm, 1.36 × 1019 cm?3, and 6.75 cm2 V?1 s?1 for the resistivity, hole concentration, and hole mobility, respectively, for film deposited at the optimum substrate temperature of 300 °C in a gas mixture of Ar and 50% N2.
关键词： deposition temperature,nitrogen content,p-type N-doped SnO2 thin film,X-ray photoelectron spectroscopy,DC magnetron sputtering,X-ray diffraction
更新于2025-09-19 17:15:36
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Interaction of Methane Concentration and Deposition Temperature in Atmospheric Laser Based CVD Diamond Deposition on Hard Metal
摘要： For laser-based plasma chemical vapour deposition (CVD) of diamond on hard metal at atmospheric pressure, without a vacuum chamber, the interaction between the deposition temperature and the methane concentration has to be understood to adjust the coating thickness, deposition duration, and medium diamond crystal size. The hypothesis of this study is that a wider range of methane concentrations could be used to deposit microcrystalline diamond coatings due to the increasing etching and deposition rates with rising deposition temperatures. The deposition of the CVD diamond coatings was carried out on K10 hard metal substrates. The process temperature and the methane concentration were varied from 650 to 1100°C and from 0.15% to 5.0%, respectively. The coatings were analysed by scanning electron and 3D laser-scanning confocal microscopy, energy dispersive X-ray and micro-Raman spectroscopy, as well as cryofracture-based microscopy analysis. The results showed that microcrystalline diamond coatings could be deposited in a wider range of methane concentrations when increasing the process temperature. The coating thickness saturates depending on the process temperature even though the methane concentration constantly increases. The coating thickness increases with an increasing deposition temperature until the cobalt diffusion hinders the deposition at the process temperature of 1100°C.
关键词： diamond film,chemical vapour deposition,hard metal,methane ratio,deposition temperature
更新于2025-09-19 17:13:59
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Optical Properties of PbS Quantum Dots deposited on Glass Employing a Supercritical CO2 Fluid Process
摘要： We studied the temperature dependence of the emission and absorption of PbS quantum dots deposited on glass by a supercritical CO2 fluid process. The results show that the emission is ruled by different transitions than the absorption, particularly at cryogenic temperatures. We found indications that these observations can be linked to the PbS concentration used to form the films in conjunction with the capability of the supercritical CO2 method to form dense homogeneous films.
关键词： absorption,photoluminescence,supercritical fluid deposition,temperature dependent,PbS
更新于2025-09-19 17:13:59
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Single-step growth of high quality CIGS/CdS heterojunctions using Pulsed Laser Deposition
摘要： This work reports on the utilization of pulsed laser deposition (PLD) for the preparation of CdS thin films and CdS/Cu(In,Ga)Se2 heterojunction structures on soda-lime glass (SLG) and Mo-coated SLG substrates, respectively, under various process conditions. Single phase, stoichiometric and high optical quality CdS films are obtained at a fluence of 1.1 J/cm2 and at deposition temperatures of 200 – 400oC. The results of this investigation were used to grow CdS on Cu(In,Ga)Se2/Mo/SLG. Both Cu(In,Ga)Se2 and CdS layers have been deposited sequentially using PLD without interrupting the influence of CdS deposition temperature on the properties of CdS/Cu(In,Ga)Se2 heterojunction has been extensively studied and is reported herein for the first time. Low series and high shunt resistances are obtained for the samples where CdS was grown at 200 and 300oC. The CdS/Cu(In,Ga)Se2 diode grown at CdS deposition temperature of 300oC exhibits the lowest ideality factor and leakage current, indicating the better quality of the diode. The results of this work demonstrate that high-quality CdS/Cu(In,Ga)Se2 diodes are obtained using pulsed laser deposition in a single-step growth process, eliminating the need for selenization of Cu(In,Ga)Se2 and the use of other growth techniques such as chemical bath deposition for CdS.
关键词： CdS deposition temperature,Electrical properties,Pulsed Laser Deposition,CdS,Optical properties,CdS/CIGS junction
更新于2025-09-16 10:30:52
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Preparation of visible-enhanced PbI2/MgO/ Si heterojunction photodetector
摘要： Fabrication and characterization of p-PbI2/MgO/n-Si photodetectors by pulsed laser deposition within (2.7-2.5) eV. The current-voltage and capacitance-voltage properties of PbI2/MgO/Si photodetector were investigated. The best responsivity of p-PbI2/MgO/n-Si photodetectors was ~ investigated using x-ray diffraction XRD, UV-Vis absorption and scanning electron microscope SEM. The XRD results revealed a single crystalline MgO with cubic structure along the (200) PLD under different deposition temperatures Ts were demonstrated for the first time. Structural, optical and morphological properties of nanostructured MgO and PbI2/MgO films were plane, while the PbI2 film deposited on MgO was a single crystalline with hexagonal phase along (001) plane. The optical energy gaps of PbI2 films deposited on MgO film were found to be perovskite solar cells, photodetectors, X-ray detectors, photoconductors, biological labeling and diagnostics, active matrix flat panel imagers, and γ-ray detectors [3, 4]. PbI2 films are usually prepared thermal evaporation, chemical methods, pulsed laser deposition, atomic layer deposition, and electron beam evaporation [5-8]. The wider optical energy gap MgO (7.3 eV at room temperature) is a non-toxic, high specific surface reactivity and cubic crystal structure with Fm-3m space group and transparent at the visible light. MgO films have been used in many [1, 2]. Lead iodide has been used in numerous applications, for example, light emitting diodes, Lead iodide has a hexagonal structure with optical band gap around 2.2eV at room temperature Keywords: PbI2; MgO; PLD; Heterojunction; Silicon; photodetector; Deposition temperature 0.88A/W at 410nm when the photodetector was prepared at Ts = 45°C.
关键词： Silicon,photodetector,MgO,Deposition temperature,PbI2,Heterojunction,PLD
更新于2025-09-11 14:15:04
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Significant improvement of the performance of ZrO2/V1-W O2/ZrO2 thermochromic coatings by utilizing a second-order interference
摘要： The paper deals with VO2-based thermochromic coatings prepared by reactive magnetron sputtering. We combine four ways how to improve the coating performance and to increase its application potential. First, reactive high-power impulse magnetron sputtering with a pulsed O2 flow control allowed us to prepare crystalline VO2 of the correct stoichiometry under highly industry-friendly deposition conditions: without any substrate bias at a low deposition temperature of 330 °C. Second, doping of VO2 by W (leading to V1-xWxO2, with x = 0.012 in this work) allowed us to shift the thermochromic transition temperature towards the room temperature (39 °C in this work), without concessions in terms of coating properties. Third, we employ ZrO2 antireflection layers both below and above the thermochromic V1-xWxO2 layer, and present an optimum design of the resulting ZrO2/V1-xWxO2/ZrO2 coatings. Most importantly, we show that while utilizing a first-order interference on ZrO2 leads one to a tradeoff between the luminous transmittance (Tlum) and the modulation of the solar transmittance (ΔTsol), utilizing a second-order interference allows one to optimize both Tlum and ΔTsol in parallel. Fourth, the crystalline structure of the bottom ZrO2 layer further improves the VO2 crystallinity and the process reproducibility. The optimum experimental values of ZrO2 thickness are in agreement with those predicted during the coating design. The results are important for the design and low-temperature fabrication of high-performance durable thermochromic VO2-based coatings for smart window applications.
关键词： Thermochromic coatings,Low deposition temperature,Antireflection layer,HiPIMS,Doping,VO2
更新于2025-09-04 15:30:14