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Current Spreading Length and Injection Efficiency in ZnO/GaN-Based Light-Emitting Diodes
摘要： We report on carrier injection features in light-emitting diodes (LEDs) based on nonintentionally doped-ZnO/p-GaN heterostructures. These LEDs consist of a ZnO layer grown by chemical-bath deposition (CBD) onto a p-GaN template without using any seed layer. The ZnO layer (～1-μm thickness) consists of a dense collection of partially coalesced ZnO nanorods, organized in wurtzite phase with marked vertical orientation, whose density depends on the concentration of the solution during the CBD process. Due to the limited conductivity of the p-GaN layer, the recombination in the n-region is strongly dependent on the spreading length of the holes, Lh, coming from the p-contact. Moreover, the evaluation of Lh is not easy and generally requires the design and the fabrication of several LED test patterns. We propose a simple and effective method to calculate Lh, just based on simple considerations on I–V characteristics, and a way to improve the injection efficiency in the n region based on a noncircular electrode geometry. In particular, an interdigitated electrode structure is proved to be more efficient in terms of hole injection from n- to p-region.
关键词： zinc oxide (ZnO) nanorods,ZnO/GaN heterostructures,ZnO/GaN-based light-emitting diodes (LEDs),contact injection,current spreading length,Chemical-bath deposition (CBD)
更新于2025-09-16 10:30:52
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Inserting dome shape microstructure for enhancement of ultraviolet photodetector performance of n-ZnO nanorods/p-Si heterojunction
摘要： A mixed intermediate layer of silica and zinc oxide (SZO) with architecturally dome-shaped microstructure is fabricated and characterized by combining a hydrothermal method and a plasma-enhanced chemical vapor deposition technique. Our results demonstrated that 200 (cid:1)C was an optimum deposition temperature for dome shape architecture SZO layer, acting as an antire?ection layer in the ultraviolet range and buffer layer for growth ZnO nanorods (NRs) arrays. Consequently, at 2.0 V reverse bias, the photo-to-dark current ratio measured with an p-Si/n-ZnONRs photodiode employing the dome-shaped SZO layer is improved by almost three orders of magnitude in the ultraviolet range as compared to that under visible-light illumination.
关键词： ZnO nanorods,Hydrothermal growth,Plasma-enhanced chemical vapor deposition,Photodiodes
更新于2025-09-16 10:30:52
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Natural Dyes Extracted from Fruits of Phyllanthus reticulatus as Sensitizers in ZnO Nanorods Based Dye Sensitized Solar Cells
摘要： DSSCs are a promising class of photovoltaic cells with the capability of generating green energy at low production cost since no expensive equipment is required in their fabrication. Zinc oxide (ZnO) nanorods were synthesized by hydrothermal method and their perfomance as photoanodes in dye-sensitized solar cells (DSSCs) employing I-/I3- as electrolyte and the dye extracts from fruits of Phyllanthus reticulatus as sensitizers was analyzed. the structural and surface characterization of the ZnO nanorods were accomplished using X- ray diffraction (XRD) analysis and high resolution scanning electron microscopy (HRSEM). XRD results revealed that the synthesized ZnO material exhibited hexagonal crystal structure which was found to be highly stable and crystallite. The dielectric properties of the ZnO nanorods were analyzed. The dye extracts were subjected to UV-Visible absorption spectroscopy analysis. The short-circuit photocurrent, the open-circuit photovoltage, and the power conversion efficiency of DSSC were measured using J-V measurement system.
关键词： Phyllanthus reticulatus,DSSC,XRD,HRSEM,ZnO nanorods
更新于2025-09-16 10:30:52
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Consequence of hot electron of Au and PbS shell thickness on photoa??electrochemical and catalytic activity of ZnO@Au@PbS nanorods for decomposition of toxic organic chemicals and Cr(VI) reduction by UV-to-near-infrared photon harvesting
摘要： In this research work, we have synthesised ZnO@Au@PbS nanorods (NRs) with different shell thickness by a facile chemical method. On introduction of Au nanoparticles (NPs) and PbS shells, the defect emission of ZnO NRs quench and the charge separation process enriches. Under simulated solar light irradiance the photoconductivity and charge transfer efficiency also escalate with Au NPs and PbS shell along with enhancing photocatalytic degradation of organic contaminant. The excitation wavelength dependent catalytic activity confirmed the significant enrichment in photocatalytic activity owing to the synergistic influence of Au NPs and PbS coating on ZnO NRs. The effect of aqueous solution pH and PbS shell thickness on photocatalytic reduction of Cr (VI) has been also explored. The possible charge transfer mechanism during the photocatalytic activity of ZnO@Au@PbS NRs is also proposed and analysed. The catalytic activity, stability and recyclability results revealed that ZnO@Au@PbS NRs are highly favourable and reusable for the environmental remedies.
关键词： UV-to-near-infrared photon harvesting,photocatalytic activity,Cr(VI) reduction,ZnO@Au@PbS nanorods,charge transfer
更新于2025-09-16 10:30:52
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Mitochondriaa??targeted Plasmonic Spiky Nanorods Augments the Clearance of Senescent Cell in Vivo
摘要： Cellular senescence is stress-induced irreversible growth arrest, and is thought to impair tissue function. The clearance of senescent cells can delay the features of senescence. Here, we report the development of plasmonic core–shell spiky nanorods (CSNRs) surface-modified with an anti- beta-2-microglobulin (aB2MG) antibody and triphenylphosphonium (TPP), to target the mitochondria in senescent cells. The results demonstrated that Near-infrared (NIR) light irradiated aB2MG–TPP@CSNRs selectively caused mitochondrial damage and cell-intrinsic apoptosis of senescent cells with relatively low NIR light power, and the ability of CSNRs to activate and amplify the immune response in vitro and in vivo was discovered. The mechanism was revealed that photo-induced reactive oxygen species (ROS) generation resulted in the senescent cell apoptosis and meanwhile immune adjuvant effect by CSNRs accelerated the clearance of senescent cells in mice. This study opens the way for the use of precisely regulated plasma nanostructures for immune adjuvant and photo-induced apoptosis for age-related senescence.
关键词： Spiky Nanorods,Senescent Cell,Immune Response,Photo-induced,Apoptosis,Plasmonic
更新于2025-09-16 10:30:52
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A new nanocomposite optical sensor based on polyurethane foam and gold nanorods for solid-phase spectroscopic determination of catecholamines
摘要： A new nanocomposite material based on gold nanorods and polyurethane foam was obtained, and a method for the determination of catecholamines with the use of this nanocomposite modified with silver nitrate was developed. The determination is based on the measuring hypsochromic shift of a short-wave surface plasmon resonance band in a diffuse reflection spectrum of the nanocomposite. This shift is caused by reduction of silver from silver ions on the surface of gold nanorods under the influence of catecholamines. Effects of time, pH, volume of the reaction mixture, concentration of silver ions, and catecholamines on the interaction were examined. The proposed method allows to determine dobutamine, epinephrine, norepinephrine and dopamine with the detection limits of 0.1, 0.07, 0.07, and 0.05 μg mL?1, respectively. The developed method can be applied to analysis of medicines.
关键词： Nanocomposite,Au nanorods,Surface plasmon resonance,Polyurethane foam,Catecholamines,Solid-phase spectroscopy
更新于2025-09-12 10:27:22
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The IR plasmonic properties of sub-wavelength ITO rod arrays predicted by anisotropic effective medium theory
摘要： Simple three-layer Fresnel equations combined with Maxwell-Garnett approximation were applied to study the IR plasmonic properties of ITO nanorods. By treating the anisotropic nanorod layer as a layer with an effective dielectric constant, and using anisotropic effective medium theory, we were able to accurately predict the surface plasmon resonance behavior of ITO nanorods with different nanorod length, spacing, and tilt angle. This model allows a fast and computationally inexpensive calculation to predict the plasmonic properties of arrayed nanorods.
关键词： IR plasmonic properties,ITO nanorods,anisotropic effective medium theory
更新于2025-09-12 10:27:22
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Nonaqueous synthesis of TiO2 nanorods using inductively coupled plasma
摘要： Titanium dioxide (TiO2) nanorods are widely used in many fields such as self-cleaning surfaces, photocatalytic lithography and pollutant control, owing to their outstanding physical, chemical and optical properties. Traditional methods for synthesizing TiO2 nanorods are mostly tedious with high cost and tremendous energy consumption. In this work, TiO2 nanorods with excellent optical, electrochemical, and hydrophilic properties were rapidly synthesized on titanium alloy (TC4) by using inductively coupled plasma (ICP) with strong chemical reactivity and high temperature characteristic. XRD patterns and SEM images confirm the conversion of TC4 into rutile TiO2 nanorods after irradiated by ICP at 800 W for only one pass, and the nanorods tend to grow longitudinally under prolonged ICP processing. Moreover, the well-developed single-crystalline feature of TiO2 nanorod is affirmed by TEM test. To reveal the growth mechanism of TiO2 nanorods, three types of substrates (polished TC4 by electrochemical polishing (ECP), polished TA2 by ECP and oxidized TC4 by anodizing) were used to grow TiO2 nanorods. However, TiO2 nanorods with good morphology were only formed on the first type of substrate due to the existence of β phase Ti, which could suppress thermal transmission between grains. In addition, the results of UV–Vis absorption spectrum, electrochemical test, and static water contact angle of the treated TC4 samples show that TiO2 nanorods synthesized by ICP possess excellent optical, electrochemical, and hydrophilic properties.
关键词： Inductively coupled plasma,Hydrophilicity,Optical property,TiO2 nanorods,Thermal oxidation
更新于2025-09-12 10:27:22
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Fabrication of arrangement-controlled and vertically grown ZnO nanorods by metal nanotransfer printing
摘要： Vertically aligned ZnO nanorods have been widely investigated for use in piezoelectric generators, photovoltaic devices, nanotemplates, photoelectrochemical applications, etc. In addition to vertical alignment, intentional arrangement of ZnO nanorods according to a careful design can enhance the device performance. In this work, we used metal nanotransfer printing to fabricate arrangement-controlled and vertically grown ZnO nanorods on both hard and flexible substrates. Highly vertical growth and periodical arrangement of the ZnO nanorods were confirmed by microscope images. Their crystallinity and photoluminescence characteristics were also investigated. Transmission spectra of the substrates show the enhancement of optical transmission after the nanorod growth. We believe that this fabrication technique lends itself to simple fabrication of arrangement-controlled and vertically grown one-dimensional nanostructures on both hard and flexible substrates for application in solar cells, water splitting, metamaterials, etc.
关键词： Zinc oxide nanorods,Flexible substrate,Intentional arrangement,Hard substrate,Nanotransfer printing
更新于2025-09-12 10:27:22
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Catalyst-Free Growth of MoS2 Nanorods Synthesized by Dual Pulsed Laser-Assisted Chemical Vapor Deposition and Their Structural, Optical and Electrical Properties
摘要： Molybdenum disulfide (MoS2) nanorods (NRs) were synthesized from bulk MoS2 using laser-assisted chemical vapor deposition. A q-switched Nd:YAG laser with combined beam wavelengths of 1064 nm and 532 nm was used to ablate a solid MoS2 target. A vapor–solid process at a furnace temperature of 1000°C was found to support the growth of MoS2 NRs without the need for any metal catalyst. Powder x-ray diffraction analysis (PXRD), field emission scanning electron microscopy, high-resolution transmission electron microscopy, Raman spectroscopy, and ultraviolet–visible (UV–Vis) and photoluminescence (PL) spectroscopy were used to characterize the structural and optical properties of MoS2 NRs. The PXRD revealed the crystallinity and phase purity of the as-synthesized NRs, while electron microscopy showed that MoS2 NRs had lengths in the range of 0.5–1.2 μm and widths between 40 nm and 160 nm. UV–Vis absorption spectra exhibited broad absorption, and PL measurements showed a sharp emission peak at 379 nm. Tauc plot calculations determined that the MoS2 NRs showed a direct transition. The electrical conductivity of the NRs was found to be 317.95 S/cm. In comparison with the MoS2 nanoparticles, the MoS2 NRs showed higher conductivity due to the in-plane electron transport, which is higher in NRs.
关键词： optical studies,MoS2,conductivity,electron microscopy,nanorods,LACVD
更新于2025-09-12 10:27:22