Search results for "Optoelectronics"
showing 10 items of 2306 documents
Electron-induced limitation of surface plasmon propagation in silver nanowires
2013
Plasmonic circuitry is considered as a promising solution-effective technology for miniaturizing and integrating the next generation of optical nano-devices. A key element is the shared metal network between electrical and optical information enabling an efficient hetero-integration of an electronic control layer and a plasmonic data link. Here, we investigate to what extend surface plasmons and current-carrying electrons interfere in such a shared circuitry. By synchronously recording surface plasmon propagation and electrical output characteristics of single chemically-synthesized silver nanowires we determine the limiting factors hindering the co-propagation of electrical current and sur…
Modelling nanoparticles formation in the plasma plume induced by nanosecond pulsed lasers
2012
International audience; Nanoparticles formation in a laser-induced plasma plume in the ambient air has been investigated by using numerical simulations and physical models. For high irradiances, or for ultrashort laser pulses, nanoparticles are formed by condensation, as fine powders, in the expanding plasma for very high pairs of temperature and pressure. At lower irradiances, or nanosecond laser pulses, another thermodynamic paths are possible, which cross the liquid-gas transition curve while laser is still heating the target and the induced plasma. In this work, we explore the growth of nanoparticles in the plasma plume induced by nanosecond pulsed lasers as a function of the laser irra…
Fast-Response Single-Nanowire Photodetector Based on ZnO/WS 2 Core/Shell Heterostructures
2018
This work was supported by the Latvian National Research Program IMIS2 and ISSP project for Students and Young Researchers Nr. SJZ/2016/6. S.P. is grateful to the ERA.Net RUS Plus WATERSPLIT project no. 237 for the financial support. S.V. is grateful for partial support by the Estonian Science Foundation grant PUT1689.
Structural and Electrical Transport Properties of Si doped GaN nanowires
2016
The control and assessment of doping in GaN nanostructures are crucial for the realization of GaN based nanodevices. In this study, we have investigated a series of Si-doped GaN nanowires (NWs) grown by molecular beam epitaxy (MBE) with a typical dimension of 2–3 µm in length, and 20–200 nm in radius. In particular, high resolution energy dispersive X-ray spectroscopy (EDX) has illustrated a higher Si incorporation in NWs than that in two-dimensional (2D) layers and Si segregation at the edge of the NW with the highest doping. Moreover, direct transport measurements on single NWs have revealed a controlled doping with resistivity from 2 × 10−2 to 10−3 Ω.cm for Si doped NWs. Field effect tra…
Silicon carbide nanowires: synthesis and cathodoluminescence
2009
Silicon carbide nanowires have been synthesized via a combustion synthesis route. Structural studies showed that obtained SiC nanowires belong dominantly to 3C polytype with zinc-blend structure. Cathodoluminescence spectra from these nanostructures within the temperature range of 77...300 K, show obvious differences with respect to the bulk materials. The exciton band of the bulk 3C-SiC is significantly damped and the prevailing line is found to be at 1.99 eV (77 K), proving the key role of defect centers in optical properties of the investigated nanomaterial.
Plasmonic Core–Satellite Assemblies as Highly Sensitive Refractive Index Sensors
2015
Highly sensitive and spectrally tunable plasmonic nanostructures are of great demand for applications such as SERS and parallel biosensing. However, there is a lack of such nanostructures for the midvisible spectral regions as most available chemically stable nanostructures offer high sensitivity in the red to far red spectrum. In this work, we report the assembly of highly sensitive nanoparticle structures using a hydroxylamine mediated core–satellite assembly of 20 nm gold nanoparticle satellites onto 60 nm spherical gold cores. The average number of satellites allows tuning the plasmon resonance wavelength from 543 to 575 nm. The core–satellite nanostructures are stable in pH ranges from…
Growth of Fe nanostructures
2004
Abstract Highly ordered arrays of epitaxial iron thin film nanostructures were grown by molecular beam epitaxy techniques on m-plane sapphire α-Al2O3 (1 0 1 0) substrates. Iron was deposited by electron beam evaporation under shallow incidence onto faceted sapphire substrates held at elevated temperatures of 450°C. Scanning electron microscopy suggests the formation of morphologically and electrically isolated nanowire structures on the ridges of the facets. The topology of the structures depends strongly on the iron deposition angle.
Optimizing Energy Transduction of Fluctuating Signals with Nanofluidic Diodes and Load Capacitors
2018
[EN] The design and experimental implementation of hybrid circuits is considered allowing charge transfer and energy conversion between nanofluidic diodes in aqueous ionic solutions and conventional electronic elements such as capacitors. The fundamental concepts involved are reviewed for the case of fluctuating zero-average external potentials acting on single pore and multipore membranes. This problem is relevant to electrochemical energy conversion and storage, the stimulus-response characteristics of nanosensors and actuators, and the estimation of the accumulative effects caused by external signals on biological ion channels. Half-wave and full-wave voltage doublers and quadruplers can…
Influence of the tip effect of a carbon nanostructure on low current electrical arc initiation
2009
During their setting off, circuit breakers and vacuum switch devices are accompanied by an electric arc whose physical and chemical properties are governed by emissive current sites at the cathode surface called cathode spots. Assuming the continuity of the current on the cathode surfaces, the cathode spots contribute to supply the electrical arc by electron emission and material ejection. Thus they cause erosion on the contact electrodes inducing a dysfunction of contactors. The apparition of these cathode spots is due essentially to dust particles and surface irregularities at different scales. This experimental work represents a contribution to the understanding of the electrical arc beh…
Resonance assisted jump-in voltage reduction for electrostatically actuated nanobeam-based gateless NEM switches.
2019
Electrostatically actuated nanobeam-based electromechanical switches have shown promise for versatile novel applications, such as low power devices. However, their widespread use is restricted due to poor reliability resulting from high jump-in voltages. This article reports a new method for lowering the jump-in voltage by inducing mechanical oscillations in the active element during the switching ON process, reducing the jump-in voltage by more than three times. Ge0.91Sn0.09 alloy and Bi2Se3 nanowire-based nanoelectromechanical switches were constructed in situ to demonstrate the operation principles and advantages of the proposed method.