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V G Dubrovskii - One of the best experts on this subject based on the ideXlab platform.

  • length distributions of nanowires growing by surface Diffusion
    Crystal Growth & Design, 2016
    Co-Authors: V G Dubrovskii, Yury Berdnikov, Jan Schmidtbauer, Mattias Borg, Kristian Storm, Knut Deppert, Jonas Johansson
    Abstract:

    We present experimental data on the time and radius-dependent length distributions of Au-catalyzed InAs nanowires grown by metal organic vapor phase epitaxy. We show that these distributions are not as sharp as commonly believed. Rather, they appear to be much broader than Poissonian from the very beginning and spread quickly as the nanowires grow. We develop a model that attributes the observed broadening to the Diffusion-induced character of growth. In the initial growth stage, the nanowires are fed from their entire length, leading to a Polya-like length distribution whose standard deviation is proportional to the mean length. After the nanowire length exceeds the Adatom Diffusion length, the growth acquires a Poissonian character in which the standard deviation scales as a square root of the mean length. We explain why wider nanowires have smaller length dispersion and speculate on the length distributions in Au-catalyzed versus self-catalyzed growth methods.

  • Diffusion induced growth of nanowires generalized boundary conditions and self consistent kinetic equation
    Journal of Crystal Growth, 2014
    Co-Authors: V G Dubrovskii, Yu Yu Hervieu
    Abstract:

    Abstract In this work, we present a theoretical analysis of the Diffusion-induced growth of “vapor–liquid–solid” nanowires, based on the stationary equations with generalized boundary conditions. We discuss why and how the earlier results are modified when the Adatom chemical potential is discontinuous at the nanowire base. Several simplified models for the Adatom Diffusion flux are discussed, yielding the 1 / R p radius dependence of the length, with p ranging from 0.5 to 2. The self-consistent approach is used to couple the Diffusion transport with the kinetics of 2D nucleation under the droplet. This leads to a new growth equation that contains only two dimensional parameters and the power exponents p and q , where q =1 or 2 depends on the nucleus position. We show that this equation describes the size-dependent depression of the growth rate of narrow nanowires much better than the Gibbs–Thomson correction in several important cases. Overall, our equation fits very well the experimental data on the length–radius correlations of III–V and group IV nanowires obtained by different epitaxy techniques.

  • gibbs thomson and Diffusion induced contributions to the growth rate of si inp and gaas nanowires
    Physical Review B, 2009
    Co-Authors: V G Dubrovskii, G. E. Cirlin, N V Sibirev, I P Soshnikov, Wanghua Chen, R Larde, E Cadel, P Pareige, Bruno Grandidier, J P Nys
    Abstract:

    We present a general model for the vapor-liquid-solid nanowire (NW) growth rates which accounts for Adatom Diffusion from the substrate and sidewalls into the Au catalyst drop as well as the Gibbs-Thomson effect of elevated chemical potential in the drop with a curved surface. The growth model is compared with the experimental length-diameter dependences for InP and Si NWs grown via metal organic chemical vapor deposition (MOCVD) and GaAs nanowires grown via molecular beam epitaxy (MBE). We show that MBE growth is affected mainly by Adatom Diffusion from the substrate, whereas MOCVD growth is affected mainly by direct Au drop impingement and sidewall Diffusion. The Gibbs-Thomson effect is shown to limit growth for smaller diameter nanowires. Fits for Diffusion lengths and the Gibbs-Thomson radii are determined which explain the experimental length-diameter dependence observed.

  • theoretical analysis of the vapor liquid solid mechanism of nanowire growth during molecular beam epitaxy
    Physical Review E, 2006
    Co-Authors: V G Dubrovskii, G. E. Cirlin, N V Sibirev, J C Harmand, V M Ustinov
    Abstract:

    A theoretical model of nanowire formation by the vapor-liquid-solid mechanism during molecular beam epitaxy and related growth techniques is presented. The model unifies the conventional adsorption-induced model, the Diffusion-induced model, and the model of nucleation-mediated growth on the liquid-solid interface. The concentration of deposit atoms in the liquid alloy, the nanowire diameter, and all other characteristics of the growth process are treated dynamically as functions of the growth time. The model provides theoretical length-diameter dependences of nanowires and the dependence of the nanowire length on the technologically controlled growth conditions, such as the surface temperature and the deposition thickness. In particular, it is shown that the length-diameter curves of nanowires might convert from decreasing to increasing at a certain critical diameter and that the nanowires taper when their length becomes comparable with the Adatom Diffusion length on the sidewalls. The theoretical dependence of the nanowire morphology on its lateral size and length and on the surface temperature are compared to the available experimental data obtained recently for Si and nanowires.

  • Diffusion induced growth of gaas nanowhiskers during molecular beam epitaxy theory and experiment
    Physical Review B, 2005
    Co-Authors: V G Dubrovskii, G. E. Cirlin, N V Sibirev, I P Soshnikov, A A Tonkikh, Yu B Samsonenko, V M Ustinov
    Abstract:

    Mechanisms of nanowhisker formation during molecular beam epitaxy (MBE) are studied theoretically within the frame of a kinetic model that accounts for the Adatom Diffusion from the surface to the top of nanowhiskers. It is shown that the Adatom Diffusion flux may considerably increase the vertical growth rate of nanowhiskers. The decreasing length/diameter dependence of the MBE grown nanowhiskers is obtained that explains a number of experimentally observed facts. The results of experimental investigations of GaAs nanowhiskers grown by MBE on the GaAs(111)B surface activated by Au at different conditions are presented and analyzed. It is shown that the length of thin GaAs nanowhiskers is several times larger than the effective thickness of deposited GaAs. Theoretical and experimental length/diameter curves are compared to each other and a good correlation between them is demonstrated.

V M Ustinov - One of the best experts on this subject based on the ideXlab platform.

  • Diffusion controlled growth of semiconductor nanowires vapor pressure versus high vacuum deposition
    Surface Science, 2007
    Co-Authors: Vladimir G. Dubrovskii, G. E. Cirlin, N V Sibirev, R A Suris, J C Harmand, V M Ustinov
    Abstract:

    Abstract Theoretical model of nanowire formation is presented, that accounts for the Adatom Diffusion from the sidewalls and from the substrate surface to the wire top. Exact solution for the Adatom Diffusion flux from the surface to the wires is analyzed in different growth regimes. It is shown theoretically that, within the range of growth conditions, the growth rate depends on wire radius R approximately as 1/ R 2 , which is principally different from the conventional 1/ R performance. The effect is verified experimentally for the MBE grown GaAs and AlGaAs wires. The dependences of wire length on the drop density, surface temperature and deposition flux during vapor pressure deposition and high vacuum deposition are analyzed and the differences between these two growth techniques are discussed.

  • theoretical analysis of the vapor liquid solid mechanism of nanowire growth during molecular beam epitaxy
    Physical Review E, 2006
    Co-Authors: V G Dubrovskii, G. E. Cirlin, N V Sibirev, J C Harmand, V M Ustinov
    Abstract:

    A theoretical model of nanowire formation by the vapor-liquid-solid mechanism during molecular beam epitaxy and related growth techniques is presented. The model unifies the conventional adsorption-induced model, the Diffusion-induced model, and the model of nucleation-mediated growth on the liquid-solid interface. The concentration of deposit atoms in the liquid alloy, the nanowire diameter, and all other characteristics of the growth process are treated dynamically as functions of the growth time. The model provides theoretical length-diameter dependences of nanowires and the dependence of the nanowire length on the technologically controlled growth conditions, such as the surface temperature and the deposition thickness. In particular, it is shown that the length-diameter curves of nanowires might convert from decreasing to increasing at a certain critical diameter and that the nanowires taper when their length becomes comparable with the Adatom Diffusion length on the sidewalls. The theoretical dependence of the nanowire morphology on its lateral size and length and on the surface temperature are compared to the available experimental data obtained recently for Si and nanowires.

  • Diffusion induced growth of gaas nanowhiskers during molecular beam epitaxy theory and experiment
    Physical Review B, 2005
    Co-Authors: V G Dubrovskii, G. E. Cirlin, N V Sibirev, I P Soshnikov, A A Tonkikh, Yu B Samsonenko, V M Ustinov
    Abstract:

    Mechanisms of nanowhisker formation during molecular beam epitaxy (MBE) are studied theoretically within the frame of a kinetic model that accounts for the Adatom Diffusion from the surface to the top of nanowhiskers. It is shown that the Adatom Diffusion flux may considerably increase the vertical growth rate of nanowhiskers. The decreasing length/diameter dependence of the MBE grown nanowhiskers is obtained that explains a number of experimentally observed facts. The results of experimental investigations of GaAs nanowhiskers grown by MBE on the GaAs(111)B surface activated by Au at different conditions are presented and analyzed. It is shown that the length of thin GaAs nanowhiskers is several times larger than the effective thickness of deposited GaAs. Theoretical and experimental length/diameter curves are compared to each other and a good correlation between them is demonstrated.

G. E. Cirlin - One of the best experts on this subject based on the ideXlab platform.

  • gibbs thomson and Diffusion induced contributions to the growth rate of si inp and gaas nanowires
    Physical Review B, 2009
    Co-Authors: V G Dubrovskii, G. E. Cirlin, N V Sibirev, I P Soshnikov, Wanghua Chen, R Larde, E Cadel, P Pareige, Bruno Grandidier, J P Nys
    Abstract:

    We present a general model for the vapor-liquid-solid nanowire (NW) growth rates which accounts for Adatom Diffusion from the substrate and sidewalls into the Au catalyst drop as well as the Gibbs-Thomson effect of elevated chemical potential in the drop with a curved surface. The growth model is compared with the experimental length-diameter dependences for InP and Si NWs grown via metal organic chemical vapor deposition (MOCVD) and GaAs nanowires grown via molecular beam epitaxy (MBE). We show that MBE growth is affected mainly by Adatom Diffusion from the substrate, whereas MOCVD growth is affected mainly by direct Au drop impingement and sidewall Diffusion. The Gibbs-Thomson effect is shown to limit growth for smaller diameter nanowires. Fits for Diffusion lengths and the Gibbs-Thomson radii are determined which explain the experimental length-diameter dependence observed.

  • Diffusion controlled growth of semiconductor nanowires vapor pressure versus high vacuum deposition
    Surface Science, 2007
    Co-Authors: Vladimir G. Dubrovskii, G. E. Cirlin, N V Sibirev, R A Suris, J C Harmand, V M Ustinov
    Abstract:

    Abstract Theoretical model of nanowire formation is presented, that accounts for the Adatom Diffusion from the sidewalls and from the substrate surface to the wire top. Exact solution for the Adatom Diffusion flux from the surface to the wires is analyzed in different growth regimes. It is shown theoretically that, within the range of growth conditions, the growth rate depends on wire radius R approximately as 1/ R 2 , which is principally different from the conventional 1/ R performance. The effect is verified experimentally for the MBE grown GaAs and AlGaAs wires. The dependences of wire length on the drop density, surface temperature and deposition flux during vapor pressure deposition and high vacuum deposition are analyzed and the differences between these two growth techniques are discussed.

  • theoretical analysis of the vapor liquid solid mechanism of nanowire growth during molecular beam epitaxy
    Physical Review E, 2006
    Co-Authors: V G Dubrovskii, G. E. Cirlin, N V Sibirev, J C Harmand, V M Ustinov
    Abstract:

    A theoretical model of nanowire formation by the vapor-liquid-solid mechanism during molecular beam epitaxy and related growth techniques is presented. The model unifies the conventional adsorption-induced model, the Diffusion-induced model, and the model of nucleation-mediated growth on the liquid-solid interface. The concentration of deposit atoms in the liquid alloy, the nanowire diameter, and all other characteristics of the growth process are treated dynamically as functions of the growth time. The model provides theoretical length-diameter dependences of nanowires and the dependence of the nanowire length on the technologically controlled growth conditions, such as the surface temperature and the deposition thickness. In particular, it is shown that the length-diameter curves of nanowires might convert from decreasing to increasing at a certain critical diameter and that the nanowires taper when their length becomes comparable with the Adatom Diffusion length on the sidewalls. The theoretical dependence of the nanowire morphology on its lateral size and length and on the surface temperature are compared to the available experimental data obtained recently for Si and nanowires.

  • Diffusion induced growth of gaas nanowhiskers during molecular beam epitaxy theory and experiment
    Physical Review B, 2005
    Co-Authors: V G Dubrovskii, G. E. Cirlin, N V Sibirev, I P Soshnikov, A A Tonkikh, Yu B Samsonenko, V M Ustinov
    Abstract:

    Mechanisms of nanowhisker formation during molecular beam epitaxy (MBE) are studied theoretically within the frame of a kinetic model that accounts for the Adatom Diffusion from the surface to the top of nanowhiskers. It is shown that the Adatom Diffusion flux may considerably increase the vertical growth rate of nanowhiskers. The decreasing length/diameter dependence of the MBE grown nanowhiskers is obtained that explains a number of experimentally observed facts. The results of experimental investigations of GaAs nanowhiskers grown by MBE on the GaAs(111)B surface activated by Au at different conditions are presented and analyzed. It is shown that the length of thin GaAs nanowhiskers is several times larger than the effective thickness of deposited GaAs. Theoretical and experimental length/diameter curves are compared to each other and a good correlation between them is demonstrated.

N V Sibirev - One of the best experts on this subject based on the ideXlab platform.

  • gibbs thomson and Diffusion induced contributions to the growth rate of si inp and gaas nanowires
    Physical Review B, 2009
    Co-Authors: V G Dubrovskii, G. E. Cirlin, N V Sibirev, I P Soshnikov, Wanghua Chen, R Larde, E Cadel, P Pareige, Bruno Grandidier, J P Nys
    Abstract:

    We present a general model for the vapor-liquid-solid nanowire (NW) growth rates which accounts for Adatom Diffusion from the substrate and sidewalls into the Au catalyst drop as well as the Gibbs-Thomson effect of elevated chemical potential in the drop with a curved surface. The growth model is compared with the experimental length-diameter dependences for InP and Si NWs grown via metal organic chemical vapor deposition (MOCVD) and GaAs nanowires grown via molecular beam epitaxy (MBE). We show that MBE growth is affected mainly by Adatom Diffusion from the substrate, whereas MOCVD growth is affected mainly by direct Au drop impingement and sidewall Diffusion. The Gibbs-Thomson effect is shown to limit growth for smaller diameter nanowires. Fits for Diffusion lengths and the Gibbs-Thomson radii are determined which explain the experimental length-diameter dependence observed.

  • Diffusion controlled growth of semiconductor nanowires vapor pressure versus high vacuum deposition
    Surface Science, 2007
    Co-Authors: Vladimir G. Dubrovskii, G. E. Cirlin, N V Sibirev, R A Suris, J C Harmand, V M Ustinov
    Abstract:

    Abstract Theoretical model of nanowire formation is presented, that accounts for the Adatom Diffusion from the sidewalls and from the substrate surface to the wire top. Exact solution for the Adatom Diffusion flux from the surface to the wires is analyzed in different growth regimes. It is shown theoretically that, within the range of growth conditions, the growth rate depends on wire radius R approximately as 1/ R 2 , which is principally different from the conventional 1/ R performance. The effect is verified experimentally for the MBE grown GaAs and AlGaAs wires. The dependences of wire length on the drop density, surface temperature and deposition flux during vapor pressure deposition and high vacuum deposition are analyzed and the differences between these two growth techniques are discussed.

  • theoretical analysis of the vapor liquid solid mechanism of nanowire growth during molecular beam epitaxy
    Physical Review E, 2006
    Co-Authors: V G Dubrovskii, G. E. Cirlin, N V Sibirev, J C Harmand, V M Ustinov
    Abstract:

    A theoretical model of nanowire formation by the vapor-liquid-solid mechanism during molecular beam epitaxy and related growth techniques is presented. The model unifies the conventional adsorption-induced model, the Diffusion-induced model, and the model of nucleation-mediated growth on the liquid-solid interface. The concentration of deposit atoms in the liquid alloy, the nanowire diameter, and all other characteristics of the growth process are treated dynamically as functions of the growth time. The model provides theoretical length-diameter dependences of nanowires and the dependence of the nanowire length on the technologically controlled growth conditions, such as the surface temperature and the deposition thickness. In particular, it is shown that the length-diameter curves of nanowires might convert from decreasing to increasing at a certain critical diameter and that the nanowires taper when their length becomes comparable with the Adatom Diffusion length on the sidewalls. The theoretical dependence of the nanowire morphology on its lateral size and length and on the surface temperature are compared to the available experimental data obtained recently for Si and nanowires.

  • Diffusion induced growth of gaas nanowhiskers during molecular beam epitaxy theory and experiment
    Physical Review B, 2005
    Co-Authors: V G Dubrovskii, G. E. Cirlin, N V Sibirev, I P Soshnikov, A A Tonkikh, Yu B Samsonenko, V M Ustinov
    Abstract:

    Mechanisms of nanowhisker formation during molecular beam epitaxy (MBE) are studied theoretically within the frame of a kinetic model that accounts for the Adatom Diffusion from the surface to the top of nanowhiskers. It is shown that the Adatom Diffusion flux may considerably increase the vertical growth rate of nanowhiskers. The decreasing length/diameter dependence of the MBE grown nanowhiskers is obtained that explains a number of experimentally observed facts. The results of experimental investigations of GaAs nanowhiskers grown by MBE on the GaAs(111)B surface activated by Au at different conditions are presented and analyzed. It is shown that the length of thin GaAs nanowhiskers is several times larger than the effective thickness of deposited GaAs. Theoretical and experimental length/diameter curves are compared to each other and a good correlation between them is demonstrated.

Raffaella Calarco - One of the best experts on this subject based on the ideXlab platform.

  • influence of the Adatom Diffusion on selective growth of gan nanowire regular arrays
    Applied Physics Letters, 2011
    Co-Authors: T Gotschke, T Stoica, Timo Schumann, F Limbach, Raffaella Calarco
    Abstract:

    Molecular beam epitaxy (MBE) on patterned Si/AlN/Si(111) substrates was used to obtain regular arrays of uniform-size GaN nanowires (NWs). The silicon top layer has been patterned with e-beam lithography, resulting in uniform arrays of holes with different diameters (dh) and periods (P). While the NW length is almost insensitive to the array parameters, the diameter increases significantly with dh and P till it saturates at P values higher than 800 nm. A Diffusion induced model was used to explain the experimental results with an effective Diffusion length of the Adatoms on the Si, estimated to be about 400 nm.

  • mechanism of molecular beam epitaxy growth of gan nanowires on si 111
    Applied Physics Letters, 2007
    Co-Authors: Ratan Debnath, R Meijers, T Richter, T Stoica, Raffaella Calarco, H Luth
    Abstract:

    GaN nanowires have been grown without external catalyst on Si(111) substrates by plasma-assisted molecular beam epitaxy. Nanowire aspect ratios (length/diameter) of about 250 have been achieved. During the initial stage of the growth, there is a nucleation process in which the number of wires increases and the most probable nucleation diameter of about 10nm has been observed, which slowly increases with deposition time. For deposition time longer than the nucleation stage, the nanowire length as a function of diameter monotonically decreases. This phenomenon can be explained by Adatom Diffusion on the nanowire lateral surface towards the tip.