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Facile and Efficient Welding of Silver Nanowires Based on UVA‐Induced Nanoscale Photothermal Process for Roll‐to‐Roll Manufacturing of High‐Performance Transparent Conducting Films
摘要： The continuous, large-area solution-processed production of silver nanowire (AgNW) transparent conducting films with outstanding optoelectronic and mechanical performance remains a challenge. Here, efficient welding of AgNWs is demonstrated using ultraviolet A (UVA) with the specific wavelength range from ≈320 to ≈400 nm based on a nanoscale photothermal process. The AgNW welding shows a self-terminating and self-limiting nature, and sensitivity to diameter of AgNWs. Sheet resistance of the UVA-illuminated (UVAI) AgNW films rapidly drops within 2 min without loss of transmittance. For the UVAI AgNW (30 nm in diameter) film, decrement of sheet resistance approaches three orders of magnitude (≈105–102 Ohm sq?1) with original transmittance being (97%) retained, which significantly enhances its optoelectronic properties. Enhanced mechanical flexibility, electromagnetic interference (EMI) shielding effectiveness (SE), and heating performance are obtained in the UVAI AgNW films. The SE and plateau temperature of the AgNW film increase to 25 dB and 50 °C after illumination, respectively. Smart window, transparent heater, and triboelectric nanogenerator based on the UVAI AgNW film demonstrate its versatile applications in optoelectronics. Finally, the welding method is easily integrated into a roll-to-roll process to manufacture AgNW film with a low sheet resistance of 25 Ohm sq?1 and a high transmittance of 90%, and excellent flexibility.
关键词： transparent conducting films,roll-to-roll process,nanoscale photothermal process,welding,silver nanowires
更新于2025-09-04 15:30:14
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A Facile Green Approach for Synthesis of Selenium Nanowires with Visible Light Photocatalytic Properties
摘要： In this work, high purity trigonal selenium (t-Se) nanowires were synthesized through a simple one-step solvothermal process at 50 °C. Sodium formaldehyde sulfoxylate (SFS) was used as a reducing agent. To our knowledge, this is the first time that SFS was used as the reducing agent for synthesis of Se nanostructures. In this method, Se nanowires were obtained at lower temperature, shorter period of reaction time and without using complex equipment. The experimental parameters, such as reaction duration, temperature and amount of surfactant, were investigated. The as-prepared Se nanowires have a diameter of about 100–200 nm and length of up to 10 μm. A “Solid–Solution–Solid” growth mechanism was proposed. In the presence of H2O2, the Se nanowires showed good catalytic performance, where over 99% of methylene blue (MB) was degraded in 3.0 h. Results from this study demonstrated that the Se nanowires exhibit a promising application for photodegradation.
关键词： Synthesis,Photocatalytic Performance,Selenium,Nanowires
更新于2025-09-04 15:30:14
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Synthesis and characterization of carbon-poor SiC nanowires via vapor-liquid-solid growth mechanism
摘要： Nanowires growth via vapor-liquid-solid mechanism leads to high-quality SiC nanowires. C content is key issue affecting the morphology and composition of SiC nanowires. Here, we report the synthesis and growth mechanism of 3C-SiC nanowires containing reduced amount of C, which are grown on single-crystal Si via pyrolysis of polycarbosilane (PCS) by adjusting pyrolysis temperature and precursor. SiC nanowires have a diameter of 50 nm, while their thickness is 43.75 μm. High-temperature stability of precursors with multiple side-chain groups has an impact on the reaction rate, in result the solid precursor state and pyrolysis temperature at 1350°C are beneficial to the formation of pure carbon-poor SiC nanowires.
关键词： precursor state,vapor-liquid-solid growth mechanism,SiC nanowires,pyrolysis temperature
更新于2025-09-04 15:30:14
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[IEEE 48th European Solid-State Device Research Conference (ESSDERC 2018) - Dresden (2018.9.3-2018.9.6)] 2018 48th European Solid-State Device Research Conference (ESSDERC) - Effect of Electron-phonon Scattering on the Thermal Conductivity of Si Nanowires
摘要： Even the effect of electron-phonon scattering on the electronic properties of Si nanowires has been widely studied, its impact on phonon transport has received much less attention. Recent experiments gave the first evidence of a doping-induced reduction of the thermal conductivity in highly B-doped (~5?×?1019?cm-3) Si nanowires with a diameter of 31?nm. Here, we present a model that can fully explain these data. We also simulated the thermal conductivity of P-doped Si nanowires and found a smaller reduction compared to the B-doped samples. Our model includes the effect of incomplete ionization due to interface states, trapped charges, and the dielectric mismatch between nanowire and its surrounding. This effect is most pronounced close to a doping level of 1018?cm-3 for B- and P-doped Si nanowires with an electronic diameter of 31?nm at room temperature. In mitigating the dielectric mismatch, both an increasing diameter and coating the nanowire by an oxide reduce the effect of incomplete ionization. At high doping concentration (~5?×?1019?cm-3) it can be neglected.
关键词： electron-phonon scattering,incomplete ionization,Si nanowires,thermal conductivity,doping
更新于2025-09-04 15:30:14
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Proposal and Realization of Vertical GaN Nanowire Static Induction Transistor
摘要： Vertical Gallium Nitride (GaN) nanowire Static Induction Transistors (SITs) are proposed and realized for micro display for the first time. A top-down dry etch was employed to form the GaN nanowires with height of ~1.5 μm and diameter of ~350 nm, followed by the SIT fabrication with the gate-all-around design which benefits are better gate control, combined with reduced surface area consumption for improved scaling and integration. Relatively low voltages are required for controlling the vertical current from source to drain. The Ion to Ioff ratio is measured as 2 × 106, which is ~900 times larger than the previous reported GaN fin SIT. These results demonstrated that vertical nanowire SITs by the use of undoped GaN which is typically the template layer for light-emitting diodes (LEDs) will enable voltage-controlled components for new integration schemes and opportunities in micro display technology.
关键词： Vertical Devices,Nanowires,Static Induction Transistor,Schottky gate,GaN
更新于2025-09-04 15:30:14
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Optoelectronic and photocatalytic properties of zinc sulfide nanowires synthesized by vapor-liquid-solid process
摘要： Zinc sul?de (ZnS) is a wide band-gap semiconductor with excellent optoelectronic properties suitable for photo-sensing devices and photocatalysts. Herein, the ZnS nanowires (ZnS NWs) have been successfully synthesized using thermal evaporation based on vapor-liquid-solid (VLS) method. From the examinations of photosensing device under ultraviolet B (UVB) irradiation, the photocurrent gain (Pg), responsivity (Rλ), response time and recovery time are 0.572, 2.761 mW/cm2, 3.2 s and 3.6 s, respectively. As to photocatalytic activity for methylene blue (MB), the apparent rate coe?cient (K) of ZnS NWs is 9.78 × 10?3 (min?1). Although ZnS NWs-based photodetector cannot be workable under ultraviolet A (UVA) irradiation, with referring to recent medical literatures, UVB radiation is the major environmental risk factor for developing human skin cancer, the most common cancer worldwide. Thus, the most important contribution in this work is that the ZnS NWs-based UVB radiation-oriented photodetector has been successfully demonstrated via a simple process.
关键词： Photodetector,Zinc sul?de nanowires (ZnS NWs),Photocurrent gain (Pg),Optoelectronic,Vapor-liquid-solid (VLS),Apparent rate coe?cient (K),Responsivity (Rλ),Ultraviolet B (UVB) irradiation
更新于2025-09-04 15:30:14
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Electrochromic Switch Devices Mixing Small- and Large-Sized Upconverting Nanocrystals
摘要： The hasty progress in smart, portable, flexible, and transparent integrated electronics and optoelectronics is currently one of the driving forces in nanoscience and nanotechnology. A promising approach is the combination of transparent conducting electrode materials (e.g., silver nanowires, AgNWs) and upconverting nanoparticles (UCNPs). Here, electrochromic devices based on transparent nanocomposite films of poly(methyl methacrylate) and AgNWs covered by UCNPs of different sizes and compositions are developed. By combining the electrical control of the heat dissipation in AgNW networks with size-dependent thermal properties of UCNPs, tunable electrochromic transparent devices covering a broad range of the chromatic diagrams are fabricated. As illustrative examples, devices mixing large-sized (>70 nm) β-NaYF4:Yb,Ln and small-sized (<15 nm) NaGdF4:Yb,Ln@NaYF4 core@shell UCNPs (Ln = Tm, Er, Ce/Ho) are presented, permitting to monitor the temperature-dependent emission of the particles by the intensity ratio of the Er3+ 2H11/2 and 4S3/2 → 4I15/2 emission lines, while externally controlling the current flow in the AgNW network. Moreover, by defining a new thermometric parameter involving the intensity ratio of transitions of large- and small-sized UCNPs, a relative thermal sensitivity of 5.88% K?1 (at 339 K) is obtained, a sixfold improvement over the values reported so far.
关键词： electrochromic materials,upconverting nanocrystals,thermal sensitivity,transparent conducting electrode materials,silver nanowires
更新于2025-09-04 15:30:14
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Design and investigation of a dual-layer grating coupler for efficient vertical fiber-chip coupling
摘要： A novel dual-layer grating coupler was designed for efficient vertical coupling between a single-mode fiber and silicon nanowires, with characteristics of polarization diversity and both wavelength bands of 1.3 and 1.55 μm. Theoretical analysis and two-dimensional finite-difference time-domain simulations were applied to verify the performance of the design. Optimized results show that the coupling efficiencies of a dual-port output of 41% (?3.87 dB) for transverse-electric polarization at 1.56 μm, 32.88% (?4.83 dB) for transverse-magnetic (TM) polarization at 1.58 μm, and 27.06% (?5.68 dB) for TM polarization at 1.32 μm can be achieved. Dual-layer Fabry–Perot resonance was also investigated for high coupling efficiency.
关键词： silicon nanowires,dual-layer grating coupler,vertical fiber-chip coupling,polarization diversity,wavelength bands
更新于2025-09-04 15:30:14
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Influence of Boron Antisite Defects on the Electrical Properties of MBE‐Grown GaAs Nanowires
摘要： Nanowires provide a platform for the integration of heterogeneous materials in III–V systems grown on Si. BxGa1(cid:1)xAs is an interesting material for strain applications, which has not yet been studied in nanowire form. The incorporation of boron in GaAs nanowires is investigated via DC-IV measurements. In transmission electron microscopy analysis a high concentration of boron is found at the nanowire edges, indicating surface segregation during growth. Nanowires grown under boron flux are found to exhibit Ohmic contacts and low contact resistances with p-type metallizations such as Au/Zn/Au or Cr/Au. Back-gated measurements confirmed the p-type behavior of such nanowires, indicating that boron is incorporated on antisite defects where it acts as a doubly-charged acceptor. This offers a new route for the inclusion of p-doped layers in GaAs-based nanowire heterostructures and the subsequent formation of Ohmic contacts.
关键词： boron doping,B:GaAs,nanowires,molecular beam epitaxy
更新于2025-09-04 15:30:14
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Insight of surface treatments for CMOS compatibility of InAs nanowires
摘要： A CMOS compatible process is presented in order to grow self-catalyzed InAs nanowires on silicon by molecular beam epitaxy. The crucial step of this process is a new in-situ surface preparation under hydrogen (gas or plasma) during the substrate degassing combined with an in-situ arsenic annealing prior to growth. Morphological and structural characterizations of the InAs nanowires are presented and growth mechanisms are discussed in detail. The major influence of surface termination is exposed both experimentally and theoretically using statistics on ensemble of nanowires and density functional theory (DFT) calculations. The differences observed between Molecular Beam Epitaxy (MBE) and Metal Organic Vapor Phase Epitaxy (MOVPE) growth of InAs nanowires can be explained by these different surfaces terminations. The transition between a vapor solid (VS) and a vapor liquid solid (VLS) growth mechanism is presented. Optimized growth conditions lead to very high aspect ratio nanowires (up to 50 nm in diameter and 3 micron in length) without passing the 410 °C thermal limit, which makes the whole process CMOS compatible. Overall, our results suggest a new method for surface preparation and a possible tuning of the growth mechanism using different surface terminations.
关键词： nanowires,growth modeling,self-catalyzed growth,hydrogen preparation,density functional theory (DFT) modeling,III-V semiconductors on silicon,InAs
更新于2025-09-04 15:30:14