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Sulfur doping of M/In <sub/>2</sub> O <sub/>3</sub> (M=Al,W) nanowires with room temperature near infra red emission
摘要： We have investigated the growth of Al doped In2O3 nanowires via the vapor-liquid-solid mechanism at 800?C using Au as a catalyst. We find that the Al is not incorporated into the cubic bixbyite crystal structure of In2O3 but nevertheless was detected in the form of Al2O3. The nanowires had metallic like conductivities and exhibited photoluminescence at 2.3 eV which shifted to 1.5 eV after exposure to H2S above 500?C due to the formation of β-In2S3 and deep donor to acceptor transitions with a lifetime of ≈ 1 μs. The near infra red emission was also observed in W/In2O3 but not in W/SnO2 core-shell nanowires after processing under H2S at 600?C, confirming it is related to β-In2S3. The nanowires remain one dimensional up to 900?C due to the shell which is interesting for the fabrication of high temperature nanowire sensors.
关键词： β-In2S3,M/In2O3 nanowires,Al doped In2O3,room temperature near infra red emission,Sulfur doping
更新于2025-09-09 09:28:46
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Nanowires for energy: A review
摘要： Semiconductor nanowires (NWs) represent a new class of materials and a shift from conventional two-dimensional bulk thin films to three-dimensional devices. Unlike thin film technology, lattice mismatch strain in NWs can be relaxed elastically at the NW free surface without dislocations. This capability can be used to grow unique heterostructures and to grow III-V NWs directly on inexpensive substrates, such as Si, rather than lattice-matched but more expensive III-V substrates. This capability, along with other unique properties (quantum confinement and light trapping), makes NWs of great interest for next generation optoelectronic devices with improved performance, new functionalities, and reduced cost. One of the many applications of NWs includes energy conversion. This review will outline applications of NWs in photovoltaics, thermoelectrics, and betavoltaics (direct conversion of solar, thermal, and nuclear energy, respectively, into electrical energy) with an emphasis on III-V materials. By transitioning away from bulk semiconductor thin films or wafers, high efficiency photovoltaic cells comprised of III-V NWs grown on Si would improve performance and take advantage of cheaper materials, larger wafer sizes, and improved economies of scale associated with the mature Si industry. The thermoelectric effect enables a conversion of heat into electrical power via the Seebeck effect. NWs present an opportunity to increase the figure of merit (ZT) of thermoelectric devices by decreasing the thermal conductivity (j) due to surface phonon backscattering from the NW surface boundaries. Quantum confinement in sufficiently thin NWs can also increase the Seebeck coefficient by modification of the electronic density of states. Prospects for III-V NWs in thermoelectric devices, including solar thermoelectric generators, are discussed. Finally, betavoltaics refers to the direct generation of electrical power in a semiconductor from a radioactive source. This betavoltaic process is similar to photovoltaics in which photon energy is converted to electrical energy. In betavoltaics, however, energetic electrons (beta particles) are used instead of photons to create electron-hole pairs in the semiconductor by impact ionization. NWs offer the opportunity for improved beta capture efficiency by almost completely surrounding the radioisotope with semiconductor material. Improving the efficiency is important in betavoltaic design because of the high cost of materials and manufacturing, regulatory restrictions on the amount of radioactive material used, and the enabling of new applications with higher power requirements.
关键词： photovoltaics,light trapping,nanowires,quantum confinement,thermoelectrics,lattice mismatch,betavoltaics,III-V materials,semiconductor,energy conversion
更新于2025-09-09 09:28:46
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Electroluminescence of intrashell transitions in Eu doped single ZnO nanowires
摘要： Tunable nanoscale light emitters are essential to accomplish future multifunctional optoelectronic nano-devices. Here, we present an approach for achieving red electroluminescence from single ZnO nanowires implanted with Europium ions. The electroluminescence is emitted mainly from the end facets of ZnO nanowires at room temperature under the application of an AC voltage. The corresponding electroluminescence spectrum is attributed to the radiative intrashell transitions of the Eu ions, while contributions from near band edge or deep level emission of the ZnO remain absent. The total intensity of the electroluminescence is linearly proportional to the length of the nanowires, whereas there is no clear correlation with other morphology factors of the nanowire based device such as the diameter. Furthermore, the underlying excitation mechanism of the electroluminescence is proposed as direct-impact excitation of Eu ions by hot electrons in the ZnO nanowires.
关键词： electroluminescence,Zinc oxide (ZnO),Europium (Eu),nanowires,rare earth elements,ion beam doping
更新于2025-09-09 09:28:46
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Optical properties of quasi-type-II structure in GaAs/GaAsSb/GaAs coaxial single quantum-well nanowires
摘要： The GaAsSb-based quantum well plays a very important role in optoelectronic devices due to its excellent wavelength tunability. When the dimension reduces, the quantum con?nement effect will take place and the quantum well in nanowires will show many interesting characteristics. GaAsSb-based quantum-well nanowires are of contemporary interest. However, the properties of the quasi-type-II structure in a single quantum well nanowire have been rarely investigated. Here, we grow GaAs/GaAs0.92Sb0.08/GaAs coaxial single quantum-well nanowires and discussed their power-dependent and temperature-dependent photoluminescence. We ?nd that due to the small band offset of conduction bands, both type-I like and type-II like emission exist in our nanowires. When electrons obtain enough thermal energy through collisions or surrounding environment, they will overcome the barrier and diffuse to the GaAs conduction band, which contributes to the type-II like recombination. These results show the optical property of the quasi-type-II quantum well in nanowires, which can pave the way toward future nanoscale quantum well devices.
关键词： GaAsSb,quasi-type-II structure,photoluminescence,quantum well,nanowires
更新于2025-09-09 09:28:46
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Enhancement of transport properties in single ZnSe nanowire field-effect transistors
摘要： Wide-gap semiconductors are excellent candidates for next-generation optoelectronic devices, including tunable emitters and detectors. ZnSe nanowire-based devices show great promise in blue emission applications, since they can be easily and reproducibly fabricated. However, their utility is limited by deep level defect states that inhibit optoelectronic device performance. The primary objective of this work is to show how the performance of ZnSe nanowire devices improves when nanowires are subjected to a post-growth anneal treatment in a zinc-rich atmosphere. We use low temperature photoluminescence spectroscopy to determine the primary recombination mechanisms and associated defect states. We then characterize the electronic properties of ZnSe nanowire field effect transistors fabricated from both as-grown and Zn-annealed nanowires, and measure an order-of-magnitude improvement to the electrical conductivity and mobility after the annealing treatment. We show that annealing reduces the concentration of zinc vacancies, which are responsible for strong compensation and high amounts of scattering in the as-grown nanowires.
关键词： electrical resistivity,II–VI semiconductors,crystal defects,carrier transport,photoluminescence,carrier mobility,nanowires
更新于2025-09-09 09:28:46
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Photoluminescence and Growth Mechanism of Oriented Hierarchical Fibrous-Like ZnO Nanowires
摘要： Oriented hierarchical fibrous-like ZnO nanowires with the diameter of about 30–50 nm and the length of about 15–30 um were successfully synthesized on the seed-coated Zn substrates by a simple two-step process. The morphology and structure of the obtained samples were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), and transmission electron microscopy (TEM). It is shown that fibrous-like ZnO nanowires with the aspect ratio of about 500～1000 present the dense reticular structure, which are grown on ZnO nanowire arrays. But beyond that, as-prepared samples are found to be good single crystalline with hexagonal wurtzite structure and preferential grow along the c-axis. A possible growth mechanism of oriented hierarchical fibrous-like ZnO nanowires is presented in detail, revealing that the synthesis of fibrous-like ZnO nanowires should be attributed to differences in the growth rate of the different crystallographic planes and the two growth ways. The photoluminescence (PL) spectra of oriented hierarchical fibrous-like ZnO nanowires grown at 240 min shows the 5 nm blue-shift and enhanced intensity property in the UV emission.
关键词： Hydrothermal Method,Fibrous-Like ZnO Nanowires,Formation Mechanism,Oriented Hierarchical,PL Property
更新于2025-09-04 15:30:14
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Advanced Materials for Electromagnetic Shielding (Fundamentals, Properties, and Applications) || Silver Nanowires as Shielding Materials
摘要： To date, several advanced materials have been developed in order to resolve the issue of electromagnetic interference (EMI). Among those materials, intrinsic conductive polymers, metal/polymer composites, and conductive filler/polymer composites (CPCs) are the most commonly used and extensively investigated. Metals and their polymeric composites presents high EMI shielding effectiveness, and thus dominate the EMI shielding materials. Being lightweight, processable, and corrosion resistant are important technical requirements for many EMI shielding applications. Intrinsic conductive polymers can well meet these requirements due to their inherent properties. However, their low conductivity largely limited their shielding effectiveness. CPCs, which incorporate the aforementioned properties of polymers and high conductivity of the fillers, have attracted great interest in recent years.
关键词： Silver Nanowires,EMI Shielding Effectiveness,Conductive Composites,Shielding Materials,Electromagnetic Interference
更新于2025-09-04 15:30:14
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Influence of low energy (keV) negative Li ion implantation on properties of electrochemically induced scaffold-based growth of PbSe nanowires
摘要： In the present work, PbSe nanowires were synthesized using restrictive template-based electrodeposition technique and implanted under vacuum with 200 keV negative Li ion at different fluences. The morphology of the nanowires was characterized by field emission scanning electron microscopy (FESEM). X-ray diffraction patterns confirmed the same crystal structure for pristine and ion implanted samples besides change in intensity of diffraction peaks were observed. Crystallite size was evaluated using modified Scherrer method and Williamson–Hall methods (UDM and USDM). Stress, strain, stacking fault, dislocation density and lattice parameters were evaluated for the pristine and ion implanted samples. UV–Vis spectroscopy results showed decrease in optical bandgap with increasing ion fluence. Photoluminescence spectra manifested decrease in emission peak with increasing ion fluence. The I–V graphs of the nanowires depicted space charge limiting current (SCLC) characteristics at higher voltage. An increase in current was observed with increase in ion fluence due to increase in free charge carriers.
关键词： PbSe nanowires,Negative Li ion implantation,Electrical properties,Structural properties,Optical properties,Electrodeposition
更新于2025-09-04 15:30:14
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One Step Nanoscale Patterning of Silver Nanowire-Nitride Heterostructures using Substrate-Assisted Chemical Etching
摘要： Nanoscale etching and patterning of noble metals such as copper, silver and gold is extremely difficult to achieve due to the low volatility of group 11 metal compounds. Here, we introduce a method of nanoscale chemical etching that utilizes reactions between H2O adsorbates and N radicals generated from electron beam-induced etching (EBIE) of a h-BN or AlN substrate to achieve efficient and highly localized chemical etching of Ag nanowires and the underlying substrate. The volatilization of noble metal nanowires by radical species generated during EBIE of the underlying substrate represents a new class of EBIE reactions, which we term ‘substrate-assisted chemical etching’.
关键词： nanoscale etching,substrate-assisted chemical etching,electron beam-induced etching,silver nanowires,noble metals
更新于2025-09-04 15:30:14
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Controllable coating polypyrrole on silicon carbide nanowires as a core-shell nanostructure: a facile method to enhance attenuation characteristics against electromagnetic radiation
摘要： Continuous polypyrrole (PPy) shells were coated on silicon carbide (SiC) nanowires to form core-shell nanostructures and the thicknesses of the shells were efficiently tuned through controlling the rate of polymerization. Compared with the composites loaded with pure SiC nanowires, the values of ε′ and ε′′ for the composites loaded with PPy@SiC nanowires were strengthened remarkably along with the increased thickness of the shells. The electromagnetic absorption (EA) bandwidth lower than ?10 and ?20 dB can be monitored in the area of 3.67-18.00 and 4.13-18.00 GHz, when 5 wt% of PPy@SiC nanowires were loaded in the composite. Meanwhile, the effective EA bandwidth can reach 6.88 GHz and the strongest reflection loss is ?58.6 dB.
关键词： dielectric properties,polypyrrole,silicon carbide nanowires,core-shell nanostructures,electromagnetic absorption
更新于2025-09-04 15:30:14