A5003024384- Nanowire Synthesis and Applications
- Semiconductor Quantum Structures and Devices
- GaN-based semiconductor devices and materials
- Semiconductor materials and interfaces
- Advancements in Semiconductor Devices and Circuit Design
- Quantum Dots Synthesis And Properties
- Silicon Nanostructures and Photoluminescence
- ZnO doping and properties
- Photonic and Optical Devices
- Ga2O3 and related materials
- Advanced Semiconductor Detectors and Materials
- Semiconductor Lasers and Optical Devices
- Semiconductor materials and devices
- Chalcogenide Semiconductor Thin Films
- Electronic and Structural Properties of Oxides
- Terahertz technology and applications
- nanoparticles nucleation surface interactions
- Spectroscopy and Laser Applications
- Quantum and electron transport phenomena
- Atmospheric Ozone and Climate
- Molecular Junctions and Nanostructures
- Plasmonic and Surface Plasmon Research
- Photonic Crystals and Applications
- Silicon Carbide Semiconductor Technologies
- Acoustic Wave Resonator Technologies
Saint Petersburg Academic University
2015-2024
Institute for Analytical Instrumentation
2015-2024
Ioffe Institute
2015-2024
St Petersburg University
2014-2024
ITMO University
2013-2024
Russian Academy of Sciences
2010-2022
Institute of Physics
2013-2022
Saint Petersburg State Electrotechnical University
2019-2021
St. Petersburg College
2019
Peter the Great St. Petersburg Polytechnic University
2014-2019
Mechanisms of nanowhisker formation during molecular beam epitaxy (MBE) are studied theoretically within the frame a kinetic model that accounts for adatom diffusion from surface to top nanowhiskers. It is shown flux may considerably increase vertical growth rate The decreasing length/diameter dependence MBE grown nanowhiskers obtained explains number experimentally observed facts. results experimental investigations GaAs by on GaAs(111)B activated Au at different conditions presented and...
We report on the Au-free molecular beam epitaxy growth of coherent GaAs nanowires directly Si(111) substrates. The is catalyzed by liquid Ga droplets formed in openings a native oxide layer at initial stage. Transmission electron microscopy studies demonstrate that are single crystals having zincblende structure along their length (apart from thin wurtzite region below droplet), regardless diameter (70--80 nm) and temperature range $(560--630\text{...
A theoretical model of nanowire formation by the vapor-liquid-solid mechanism during molecular beam epitaxy and related growth techniques is presented. The unifies conventional adsorption-induced model, diffusion-induced nucleation-mediated on liquid-solid interface. concentration deposit atoms in liquid alloy, diameter, all other characteristics process are treated dynamically as functions time. provides length-diameter dependences nanowires dependence length technologically controlled...
We present a general model for the vapor-liquid-solid nanowire (NW) growth rates which accounts adatom diffusion from substrate and sidewalls into Au catalyst drop as well Gibbs-Thomson effect of elevated chemical potential in with curved surface. The is compared experimental length-diameter dependences InP Si NWs grown via metal organic vapor deposition (MOCVD) GaAs nanowires molecular beam epitaxy (MBE). show that MBE affected mainly by substrate, whereas MOCVD direct impingement sidewall...
We report on the new mode of vapor−liquid−solid nanowire growth with a droplet wetting sidewalls and surrounding rather than resting its top. It is shown theoretically that such an unusual configuration happens when catalyzed by lower surface energy metal. A model nonspherical elongated shape in case developed. Theoretical predictions are compared to experimental data Ga-catalyzed GaAs nanowires molecular beam epitaxy. In particular, it demonstrated experimentally observed indeed...
Nonradiating electromagnetic configurations in nanostructures open new horizons for applications due to two essential features: lack of energy losses and invisibility the propagating field. Such radiationless form a basis types nanophotonic devices, where strong field confinement can be achieved together with lossless interactions between nearby components. In our work, we present design free-standing disk nanoantennas nonradiating current distributions optical near-infrared range. We show...
The Au-assisted molecular beam epitaxial growth of InAs nanowires is discussed. In situ reflection high-energy electron diffraction observations phase transitions the catalyst particles indicate that they can be liquid below eutectic point Au-In alloy. temperature range where covers we observed nanowire formation (380–430 °C). variation rate with investigated. Pure axial at high while mixed axial/lateral occurs low temperature. change shape duration studied. It shown significant lateral...
We report on the fabrication by Au-assisted molecular beam epitaxy of InP nanowires with embedded InAsP insertions. The growth temperature affects nucleation nanowire lateral surface. It is therefore possible to grow wires in two steps: fabricate an axial heterostructure (at 420 °C), and then cover it a shell 390 °C). alloy composition could be varied between InAs0.35P0.65 InAs0.5P0.5 changing As P flux ratio. When present, segments show strong room-temperature photoluminescence peak...
Abstract We report on the growth properties of InAs, InP and GaAs nanowires (NWs) different lattice mismatched substrates, in particular, Si(111), during Au‐assisted molecular beam epitaxy (MBE). show that critical diameter for epitaxial dislocation‐free III–V NWs decreases as mismatch increases equals 24 nm InAs 39 44 GaAs(111)B, 110 Si(111). When diameters exceed these values, are dislocated or do not grow at all. The corresponding temperature domains NW extend from 320 °C to 340 330 360...
This paper reports on the growth, structural and optical properties of GaN free-stranding nanowires synthesized in catalyst-free mode Si(111) substrate by plasma-assisted molecular beam epitaxy. Cylindrical with a hexagonal cross-section defined planes diameters down to 20 nm were observed. The nanowire length increases as function their diameter, following Gibbs–Thomson expression. growth rate lateral direction was studied using thin AlN marker layers showing that over axial ratio can be...
Molecular beam epitaxial growth of GaAs nanowires using Au particles as a catalyst was investigated. Prior to the during annealing, alloyed with Ga coming from substrate, and melted. Phase transitions resulting were observed in situ by reflection high-energy electron diffraction (RHEED). The temperature domain which nanowire is possible determined. lower limit this (320 °C) close solidification temperature. Below temperature, buried growth. Above higher (620 °C), segregates on surface no...
We study theoretically and experimentally nonlinear effects during the ``vapor-liquid-solid'' growth of semiconductor nanowires. Nonlinear equation considered contains kinetic coefficients from surface sidewall diffusion which can be either signs. predict four possible scenarios: (I) infinite growth; (II) decomposition; (III) averaging to a finite length; (IV) continuing such that nanowires small initial length decay longer grow infinitely. present experimental evidence nontrivial scenarios...
Quantum dots tuned to atomic resonances represent an emerging field of hybrid quantum systems where the advantages and natural atoms can be combined. Embedding in nanowires boosts these with a set powerful possibilities, such as precise positioning emitters, excellent photon extraction efficiency direct electrical contacting dots. Notably, nanowire structures grown on silicon substrates, allowing for straightforward integration silicon-based photonic devices. In this work we show controlled...
The stress-driven formation of coherent islands in heteroepitaxial systems is studied within the frame kinetic theory nucleation under dynamical conditions. model for a description time evolution island size distribution and wetting layer thickness Stranski-Krastanow growth mode developed. scale hierarchy stage, relaxation stage critical enable us to construct analytical solutions equations. dependence lateral distribution, thickness, other characteristics process are calculated. Analytical...
We have determined the in-plane orientation of GaN nanowires relative to Si (111) substrate on which they were grown. used x-ray diffraction pole figure measurements evidence two types crystallographic orientation, all having [Formula: see text] lateral facets. The proportion these orientations was and shown be influenced by pre-deposition Al(Ga)N intermediate layers. In main basal directions are aligned with directions. This corresponds an coincidence lattices.
The influence of shadow effect originating from the neighboring nanowires on nanowire growth is theoretically investigated. axial and radial rates shape are shown to be strongly dependent surface density direction incident flux. Theoretical predictions compared with experimental shapes InAs grown by Au-catalyzed molecular beam epitaxy. In particular, barrel-like observed in dense arrays well described model. Very importantly, we show that helps avoid otherwise enabled preserve cylindrical shape.
Based on the high-angle annular dark-field scanning transmission electron microscopy and energy dispersive X-ray spectroscopy studies, we unravel origin of spontaneous core–shell AlGaAs nanowires grown by gold-assisted molecular beam epitaxy. Our have a cylindrical core tapered shell. The composition shell is close to nominal, while aluminum content in systematically smaller than nominal. After switching off group III fluxes, droplet topmost part nanowire rapidly tends zero, gallium remains...
In this work, we report an optical method for characterizing crystal phases along single-semiconductor III–V nanowires based on the measurement of polarization-dependent second-harmonic generation. This powerful imaging is a per-pixel analysis second-harmonic-generated signal incoming excitation polarization. The dependence generation responses nonlinear second-order susceptibility tensor allows distinguishing areas pure wurtzite, zinc blende, and mixed rotational twins structures in...
We bury vertical free-standing core−shell GaAs/AlGaAs nanowires by a planar GaAs overgrowth. As the get buried, their crystalline structure progressively transforms: whereas upper emerging part retains its initial wurtzite structure, buried adopts zinc blende of burying layer. The process also suppresses all stacking faults that existed in nanowires. consider two possible mechanisms for structural transition upon burying, examine how they can be discriminated from each other, and explain why...
The effect of sidewall nucleation on nanowire morphology is studied theoretically. model provides a semiquantitative description radius as function its length and the distance from surface. It demonstrated that wire shape critically depends diffusion flux adatoms substrate rate direct impingement to sidewalls. At high cylindrical. A decrease surface leads onset sidewalls resulting in lateral extension reduction length. changes cylindrical conical, because supersaturation driving higher at...
We report on the molecular beam epitaxy growth of Au-assisted GaAs p-type-doped NW arrays n-type GaAs(111)B substrate and their photovoltaic properties. The samples are grown at different temperature within range from 520 to 580 °C. It is shown that dependence conversion efficiency has a maximum 550 For best sample, 1.65% fill factor 25% obtained.
We report on the growth and electro-optical studies of photovoltaic properties GaAsP nanowires. Low density nanowires were grown by Au assisted MOVPE Si(001) substrates using a two step procedure to form radial p–n junction. The STEM analyses show that have cubic structure with alloy composition GaAs0.88P0.12 in nanowire core GaAs0.76P0.24 shell. ensembles processed sub-millimeter size mesas. characterized optical beam induced current (OBIC) electronic (EBIC) maps. Both OBIC EBIC maps...