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- Display Metrology
- dSiPM
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- Complementary Metal Oxide Semiconductor
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- The University of Edinburgh
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Structural, morphological, composition and optical properties of undoped zinc oxide thin films prepared by spray pyrolysis method: effect of solution concentrations
摘要： The aim of this paper is the study of transparent undoped zinc oxide thin films obtained by spray pyrolysis technique on glass substrates heated at 350 °C from 0.1 to 0.4 mol solution concentrations using zinc acetate dehydrate as precursor. The X-ray diffraction patterns and Raman spectrometry with respect to Urbach energy and wurtzite structure, show that the maximum value of the high frequency intensity E2 and the optimal value of the optical gap are obtained at 0.2 mol concentration. Furthermore, an appropriate transparency is obtained and that makes these films suitable for photovoltaic windows layer cells.
关键词： X-ray diffraction,ultraviolet transmission spectroscopy,Raman spectroscopy,spray pyrolysis,undoped zinc oxide
更新于2025-09-23 15:23:52
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Evolution of the infrared emissivity of Ni during thermal oxidation until oxide layer opacity
摘要： The mid-infrared (3–22 μm) emissivity of high-purity Ni has been studied in its pure state, during an isothermal oxidation in air at 730 °C and in the fully oxidized state. Measurements in pure Ni were performed in Ar between 200 and 800 °C and a change of slope in the temperature dependence of the total normal emissivity around its Curie temperature (354 °C) was observed. An oxidation process was carried out at 730 °C for 33 days, when the emissivity stopped evolving and the results were representative of NiO. During the ?rst stages, the emissivity evolved forming the usual interference patterns of semi-transparent ?lms. A mixture of oscillatory and monotonic behaviours of the emissivity as a function of wavelength and oxide layer thickness was found, which manifests as a non-trivial evolution of the total normal emissivity, di?erent than that reported in previous studies. Finally, the emissivity of NiO was measured from below its Néel temperature (252 °C) to 850 °C. It showed the typical shape of a ceramic material with an extra vibrational mode due to two-phonon processes and an additional absorption band around 5 μm in the antiferromagnetic phase produced by magnons. The temperature dependence of its total normal emissivity di?ers signi?cantly from that of a lightly oxidized nickel sample from the literature. Overall, the in?uence of the surface characteristics on the thermal radiative properties of oxidized Ni is thoroughly discussed and highlights the importance of accounting for all possible sources of infrared emissivity evolution in order to make accurate radiative heat transfer calculations.
关键词： Nickel oxide,Infrared emissivity,Radiometry,Radiative heat transfer,Magnetic phase transition,Nickel,Oxidation
更新于2025-09-23 15:23:52
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Scalable modulation of reduced graphene oxide properties via regulating graphite oxide precursors
摘要： Here we demonstrate the scalable modulation of reduced graphene oxide (RGO) properties by regulating graphite oxide (GtO) precursors. Our findings show the thickness and loose degree of GtO precursors act as key roles in flame activation process. Interestingly, the looser GtO transforms into RGO with a lower specific surface area (SSA); RGO from the thinner GtO paper shows a higher SSA. By regulating GtO precursors, SSA from 1030.5 to 335.3 m2 g?1, defect degree, oxidation degree, and pore volume from 4.61 to 1.36 cm3 g?1 can be tuned. The corresponding structural properties are translated into unique supercapacitor (SC) performances such as high specific capacitance (the highest value of 576 F g?1) and coulombic efficiency. Additionally, this method indicates great potential to prepare RGO-based metal oxide composites with good homogeneity and good SC behaviors.
关键词： Flame,Energy efficiency,Reduced graphene oxide,Precursor,Supercapacitor
更新于2025-09-23 15:23:52
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Creation of passivated Nb/N p-n co-doped ZnO nanoparticles and their enhanced photocatalytic performance under visible light illumination
摘要： Passivated niobium/nitrogen (Nb-N) p-n co-doped zinc oxide nanoparticles were created by a simple precipitation process with in-situ self-formed NaCl "cage" to confine the nanoparticle growth followed by the heat treatment in a flow of ammonia gas. Enhanced optical absorbance into the visible light region was observed in the Nb/N co-doped ZnO nanoparticle photocatalyst due to the Nb/N co-doping effect. It demonstrated a largely enhanced photocatalytic performance in the disinfection of Escherichia coli bacteria under visible light illumination, which could be attributed to the passivated co-doping of Nb-N to suppress the photogenerated charge carrier recombination on dopants. This robust approach for passivated p-n co-doping may also be applied to other material systems for a wide range of technical applications.
关键词： Nanoparticles,Passivated Nb/N p-n Co-doping,Photocatalyst,Zinc oxide,Visible light
更新于2025-09-23 15:23:52
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Effect of the synthesis method on the properties of lithium doped graphene oxide composites with tin oxide nanoparticles: Towards white luminescence
摘要： Graphene oxide (GO) based composites functionalized with nanoparticles are emerging as potential candidates for multifunctional devices. As the synthesis route can strongly influence the way in which the nanoparticles are anchored to GO and the resulting properties, different routes have been employed and evaluated in this work for the preparation of composites formed by GO and undoped or Li doped SnO2 nanoparticles. Promotion of synergetic effects, as well as changes in the structural and luminescent properties of the composites have been also analyzed. In comparison with GO, composite samples synthesized in this work involve enhanced luminescence while retaining nearly white emission, which could lead to wider applicability of GO based composites in free standing and emitting and sensing devices. Aspects, such as GO reduction, stabilization of different Sn-based oxides, variation in the concentration of oxygen related functional groups, changes in the sp2 domain sizes, incorporation of lithium and enhancement of the luminescence, have been analyzed in this work by means of x-ray diffraction (XRD), high resolution transmission electron microscopy (HRTEM), energy dispersive x-ray spectroscopy (EDS), Raman spectroscopy, x-ray photoelectron spectroscopy (XPS) and photoluminescence (PL) characterizations.
关键词： Nanoparticles,Lithium,Tin oxide,Nanomaterials,Luminescence,Composite
更新于2025-09-23 15:23:52
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Evolution of microstructures and optical properties of gadolinium oxide with oxygen flow rate and annealing temperature
摘要： In this study, the effects of oxygen flow rate and annealing temperature on Gd2O3 structures and optical properties were systematically analyzed. Gd2O3 films were deposited on both quartz and ZnS substrates by magnetron sputtering and then annealed under vacuum at 700, 800, and 900 (cid:1). Restructure and phase transformation from cubic to monoclinic occur at different temperatures depending on the oxygen flow rate. The optical band gap, which is more sensitive to the annealing temperature than oxygen flow rate changes from 5.32 to 5.65 eV. The refractive index is approximately 1.75 at 550 nm and is adjustable by the oxygen flow rate. The transmittance of the ZnS substrate with Gd2O3 film exceeds 80% and reaches 82% at the 7.5–9.5 μm range. When ZnS is coated on both sides, the transmittance is increased to approximately 90%. Our results indicate that Gd2O3 films are promising new candidates for anti-reflective coatings in the infrared region.
关键词： Rare earths,Infrared materials,Structures,Optical properties,Gadolinium oxide,Magnetron sputtering
更新于2025-09-23 15:23:52
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Shining black nanoscopic ternary zincospiroffite: A panchromatic light harvester for depollution
摘要： Nanostructured zincospiroffite (Zn2Te3O8), a promising photocatalyst for water purification and bacterial inhibition is reported for the first time. Sparkling black Zn2Te3O8 nanocrystals have been synthesized via template-free solvothermal method with minimum precursors, zinc acetate and tellurium powder, in a polymeric medium of beta-aminoethylamine. Optical and structural characterizations prove the crystalline nature and panchromatic light harvesting behavior of zincospiroffite. X-ray photoelectron spectroscopy, Raman analysis and electron paramagnetic resonance (EPR) spectroscopy provide evidence for the anion deficiency in the crystals. A 3D crystal structure derived from XRD data confirms the bonding states. Panchromatic light harvesting behavior and reactive oxygen species generation from this unexplored semiconductor help visible to near IR driven photocatalysis and unprecedently high antibacterial activity.
关键词： Zn2Te3O8,Bacterial inhibition,Photocatalyst,Ternary metal oxide
更新于2025-09-23 15:23:52
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Unique electromagnetic loss properties of Co-doped ZnO Nanofiber
摘要： In this paper, Co-doped ZnO nanoparticle and nano?ber are prepared by electrospinning method. The results show that Co-doped ZnO nano?ber performs bead-like ?brous shape and exhibits ferromagnetic properties. The dielectric loss and magnetic loss properties of Co-doped ZnO nano?ber are much better than those of Co-doped ZnO nanoparticle due to the improvement of dipole polarization, interfacial polarization and shape anisotropy. The absorptivity of Co-doped ZnO nano?ber can reach 70% in the frequency range of 5.3–18 GHz when the coating thickness is 1.5–4.0 mm. It is demonstrated that the bead-like ?brous shape is bene?cial to optimize electromagnetic loss and microwave absorption properties of Co-doped ZnO.
关键词： Electronic materials,Electromagnetic loss,Magnetic materials,Zinc oxide
更新于2025-09-23 15:23:52
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Influence of Cr doping on Schottky barrier height and visible light detection of ZnO thin films deposited by magnetron sputtering
摘要： A comparative study of the electrical and photodetection properties of ZnO and Cr doped ZnO thin films are being reported here. The films were deposited using magnetron sputtering. X-ray diffraction (XRD) revealed hexagonal crystal structure of the films with (002) preferred orientation. Pt/ZnO/Pt and Pt/Cr doped ZnO/Pt Schottky diodes were fabricated for photodetection studies. The Schottky barrier height was lowered for Cr doped ZnO film as compared to ZnO film. The ideality factor was improved upon Cr doping. Pt/ZnO/Pt diode was unresponsive to visible light, however, Pt/Cr doped ZnO/Pt diode showed response to visible light with short response and recovery times. The response of the Pt/Cr doped ZnO/Pt diodes to visible light is attributed to the reduction in band gap of the Cr doped ZnO thin film.
关键词： Thin films,Schottky contact,Chromium-doped Zinc oxide,Sputtering,Photodetectors
更新于2025-09-23 15:23:52
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[IEEE 2018 International Flexible Electronics Technology Conference (IFETC) - Ottawa, ON, Canada (2018.8.7-2018.8.9)] 2018 International Flexible Electronics Technology Conference (IFETC) - A High Speed Programmable Ring Oscillator Using InGaZnO Thin-Film Transistors
摘要： This paper presents a high speed digitally programmable Ring Oscillator (RO) using Indium-gallium-zinc oxide thin-film transistors (IGZO TFTs). Proposed circuit ensures high speed compared to the conventional ROs using negative skewed scheme, in which each inverter delay is reduced by pre-maturely switching on/off the transistors. In addition, by controlling the load capacitance of each inverter through digital control bits, a programmable frequency of oscillation was attained. Proposed RO performance is compared with two conventional designs under same conditions. From simulation, it has been observed that the proposed circuit has shown a higher frequency of oscillations (283 KHz) compared to the conventional designs (76.52 KHz and 144.9 KHz) under same conditions. Due to the programmable feature, the circuit is able to generate 8 different linearly spaced frequencies ranging from 241.2 KHz to 283 KHz depending upon three digital control bits with almost rail-to-rail voltage swing. The circuit is a potential on-chip clock generator in many real-world flexible systems, such as, smart packaging, wearable devices, RFIDs and displays that need multi frequencies.
关键词： negative skewed and rail-to-rail logic,High speed programmable RO,Oxide TFTs
更新于2025-09-23 15:23:52