scholarly journals Reconsideration of Nanowire Growth Theory at Low Temperatures

Nanomaterials ◽  
2021 ◽  
Vol 11 (9) ◽  
pp. 2378
Author(s):  
Vladimir G. Dubrovskii
Keyword(s):  
Radial Growth ◽  
Material Balance ◽  
Linear Increase ◽  
Nanowire Growth ◽  
Group Iii ◽  
Selective Area ◽  
Nanowire Surface ◽  
Gaas Nanowire ◽  
Metal Catalyzed ◽  
Kinetics Of

We present a growth model that describes the nanowire length and radius versus time in the absence of evaporation or scattering of semiconductor atoms (group III atoms in the case of III-V NWs) from the substrate, nanowire sidewalls or catalyst nanoparticle. The model applies equally well to low-temperature metal-catalyzed or selective area growth of elemental or III-V nanowires on patterned substrates. Surface diffusion transport and radial growth on the nanowire sidewalls are carefully considered under the constraint of the total material balance, yielding some new effects. The nanowire growth process is shown to proceed in two steps. In the first step, the nanowire length increases linearly with time and is inversely proportional to the nanowire radius squared and the nanowire surface density, without radial growth. In the second step, the nanowire length obeys the Chini equation, resulting in a non-linear increase in length with time and radial growth. The nanowire radii converge to a stationary value in the large time limit, showing a kind of size-narrowing effect. The model fits the data on the growth kinetics of a single self-catalyzed GaAs nanowire on a Si substrate well.

scholarly journals GaAs nanowire growth on polycrystalline silicon thin films using selective-area MOVPE

2013 ◽  
Vol 24 (11) ◽  
pp. 115304 ◽  
Author(s):  
Keitaro Ikejiri ◽  
Fumiya Ishizaka ◽  
Katsuhiro Tomioka ◽  
Takashi Fukui
Keyword(s):  
Thin Films ◽  
Polycrystalline Silicon ◽  
Nanowire Growth ◽  
Silicon Thin Films ◽  
Selective Area ◽  
Gaas Nanowire

scholarly journals Self-consistent modeling of MBE self-catalyzed GaAs nanowire growth

2021 ◽  
Vol 2086 (1) ◽  
pp. 012008
Author(s):  
S V Fedina ◽  
A A Koryakin ◽  
V V Fedorov ◽  
G A Sapunov ◽  
I S Mukhin
Keyword(s):  
Molecular Beam ◽  
Growth Conditions ◽  
Nanowire Growth ◽  
Material Transport ◽  
Evaporation Coefficient ◽  
Catalyst Droplet ◽  
Gaas Nanowires ◽  
Gaas Nanowire ◽  
The Given ◽  
Kinetics Of

Abstract Self-catalyzed GaAs nanowires are synthesized by molecular beam epitaxy at various arsenic fluxes and growth temperatures. The growth of GaAs nanowires is simulated considering the kinetics of material transport inside the catalyst droplet. The re-evaporation coefficient of arsenic is estimated for the given growth conditions. Calculated nanowire growth rate is in satisfactory agreement with the experimental data.

scholarly journals Theory of MBE Growth of Nanowires on Reflecting Substrates

Nanomaterials ◽  
2022 ◽  
Vol 12 (2) ◽  
pp. 253
Author(s):  
Vladimir G. Dubrovskii
Keyword(s):  
Radial Growth ◽  
Molecular Beam ◽  
Intermediate Stage ◽  
Selective Area Growth ◽  
Mbe Growth ◽  
Group Iii ◽  
Selective Area ◽  
Area Growth ◽  
Shadowing Effect ◽  
Axial Growth

Selective area growth (SAG) of III-V nanowires (NWs) by molecular beam epitaxy (MBE) and related epitaxy techniques offer several advantages over growth on unpatterned substrates. Here, an analytic model for the total flux of group III atoms impinging NWs is presented, which accounts for specular re-emission from the mask surface and the shadowing effect in the absence of surface diffusion from the substrate. An expression is given for the shadowing length of NWs corresponding to the full shadowing of the mask. Axial and radial NW growths are considered in different stages, including the stage of purely axial growth, intermediate stage with radial growth, and asymptotic stage, where the NWs receive the maximum flux determined by the array pitch. The model provides good fits with the data obtained for different vapor–liquid–solid and catalyst-free III-V NWs.

scholarly journals The Growth Kinetics of RhizoctoniasolaniAfter 1 MeV Electron Irradiation

2022 ◽  
Author(s):  
Ulyana Bliznyuk ◽  
Natalya Chulikova ◽  
Anna Malyuga
Keyword(s):  
Radial Growth ◽  
Radiation Treatment ◽  
Dose Range ◽  
Black Scurf ◽  
Phytopathogenic Fungus ◽  
Complete Suppression ◽  
Electron Radiation ◽  
Bacterial Diseases ◽  
Wide Range ◽  
Kinetics Of

Crops, especially potatoes, are prone to a wide range of fungal, viral and bacterial diseases, including black scurf caused by Rhizoctoniasolani. This study focused on the radiation treatment of the phytopathogenic fungus RhizoctoniasolaniKuhn, grown from sclerotium irradiated with 1 MeV electrons in the dose range from 20 to 4500 Gy. The doses absorbed by the sclerotia were determined using computer simulation. The growth of the fungus samples was monitored after 24, 48, 72, and 96 hours from the time of seeding. It was found that the dependence of the radial growth velocity of R. solani on the time after irradiation with doses ranging from 20to 1800 Gywas nonlinear. Irradiation at a dose over 4500 Gyled to complete suppression of the germination of R. solani sclerotia. Keywords: radiation treatment, electron radiation, radiation dose, sclerotia of Rhizoctoniasolani, Kuhn, radial velocity of growth

scholarly journals Study of the regularity of the process of decomposition of apatite with sulfuricacid at the boilingpoint of the solution

2019 ◽  
Vol 58 (4) ◽  
pp. 119-122
Author(s):  
Rauf F. Sabirov ◽  
◽  
Alexey F. Makhotkin ◽  
Yury N. Sakharov ◽  
Igor A. Makhotkin ◽  
...  
Keyword(s):  
Sulfuric Acid ◽  
Phosphoric Acid ◽  
Boiling Point ◽  
Batch Reactor ◽  
Material Balance ◽  
Mercury Thermometer ◽  
Experimental Values ◽  
Kinetics Of ◽  
Liquid And Solid Phases ◽  
Phosphoric Acids

Experimental research of the kinetics of the decomposition process of Kovdorsky apatite with a size = 0.16 mm with sulfuric acid in a 1 dm3 batch reactor. Phosphoric acid with the concentration of 68.6 % wt and the sulfuric acid with the concentration of 12.3% wt in stoichiometric amount was introduces at the beginning of the process. The process was carried out at a ratio of liquid and solid phases 2.5:1 respectively at the boiling point of the mixture equal to 136 °C. The observing the progress was carried out according to the method of joint designation of sulfuric and phosphoric acids by titrimetric analysis. With methyl orange and then phenolphthalein 2 titration jumps were recorded, the first of which corresponded to the neutralization of sulfuric acid to Na2SO4 and phosphoric acid to NaH2PO4, the second to the neutralization of NaH2PO4 to Na2HPO4. The change in temperature of the reaction mixture was fixed during the process using a mercury thermometer. In the analysis of the derived experimental values of specified parameters that the boiling point decreases from 136 to 133.1 оС within 50 minutes during the process. A comparison of the reported values with the concentration values of sulfuric and phosphoric acids measured during the process shows that the change in boiling point of the reaction mixture is proportional to the change in the concentrations of sulfuric and phosphoric acids. This model is a closed system that provides thermal insulation and no loss of material balance. Thus, the kinetics of the decomposition of apatite with sulfuric acid at the boiling point can be monitored by the temperature change under specified conditions.

Non-linear Surface Reaction Kinetics of GaAs MOVPE Explored by Selective Area Growth

2019 ◽  
Vol 2 (7) ◽  
pp. 145-156
Author(s):  
Haizheng Song ◽  
M. Sugiyama ◽  
Yoshiaki Nakano ◽  
Yukihiro Shimogaki
Keyword(s):  
Reaction Kinetics ◽  
Surface Reaction ◽  
Selective Area Growth ◽  
Selective Area ◽  
Area Growth ◽  
Non Linear ◽  
Surface Reaction Kinetics ◽  
Kinetics Of

scholarly journals Kinetics and mechanism of planar nanowire growth

2019 ◽  
Vol 117 (1) ◽  
pp. 152-160 ◽  
Author(s):  
Amnon Rothman ◽  
Vladimir G. Dubrovskii ◽  
Ernesto Joselevich
Keyword(s):  
Surface Diffusion ◽  
Large Scale ◽  
Nanowire Growth ◽  
Power Exponent ◽  
Material Transport ◽  
Guided Growth ◽  
Large Scale Integration ◽  
Scale Integration ◽  
And Control ◽  
Kinetics Of

Surface-guided growth of planar nanowires offers the possibility to control their position, direction, length, and crystallographic orientation and to enable their large-scale integration into practical devices. However, understanding of and control over planar nanowire growth are still limited. Here, we study theoretically and experimentally the growth kinetics of surface-guided planar nanowires. We present a model that considers different kinetic pathways of material transport into the planar nanowires. Two limiting regimes are established by the Gibbs–Thomson effect for thinner nanowires and by surface diffusion for thicker nanowires. By fitting the experimental data for the length–diameter dependence to the kinetic model, we determine the power exponent, which represents the dimensionality of surface diffusion, and results to be different for planar vs. nonplanar nanowires. Excellent correlation between the model predictions and the data is obtained for surface-guided Au-catalyzed ZnSe and ZnS nanowires growing on both flat and faceted sapphire surfaces. These data are compared with those of nonplanar nanowire growth under similar conditions. The results indicate that, whereas nonplanar growth is usually dominated by surface diffusion of precursor adatoms over the nanowire walls, planar growth is dominated by surface diffusion over the substrate. This mechanism of planar nanowire growth can be extended to a broad range of material–substrate combinations for higher control toward large-scale integration into practical devices.

Sign in / Sign up

Export Citation Format

Share Document