Ga-assisted catalyst-free growth mechanism of GaAs nanowires by molecular beam epitaxy

Colombo, Carlo; Spirkoska, D.; Frimmer, Martin; Abstreiter, G.; Morral, Anna Fontcuberta i

doi:10.1103/physrevb.77.155326

Cited by 412 publications

(529 citation statements)

References 16 publications

Supporting

Mentioning

486

Contrasting

Unclassified

Order By: Relevance

“…The growth rate of the nanowire is given by the As 4 flux. 50 The samples presented in this paper have been obtained at arsenic pressures between 3 ϫ 10 −6 and 3 ϫ 10 −7 mbar, which represent growth rates, respectively, between 3 and 0.3 m / h. We have shown in the past that a reduction in the growth rate results in an increase in the fraction of wurtzite in the nanowire. 51 The structure of the nanowires was studied by highresolution transmission electron microscopy ͑HRTEM͒ in a Philips/FEI CM 300.…”

Section: Methodsmentioning

confidence: 99%

See 1 more Smart Citation

Raman spectroscopy of wurtzite and zinc-blende GaAs nanowires: Polarization dependence, selection rules, and strain effects

et al. 2009

Self Cite

View full text Add to dashboard Cite

Polarization-dependent Raman scattering experiments realized on single GaAs nanowires with different percentages of zinc-blende and wurtzite structure are presented. The selection rules for the special case of nanowires are found and discussed. In the case of zinc-blende, the transversal optical mode E 1 ͑TO͒ at 267 cm −1 exhibits the highest intensity when the incident and analyzed polarization are parallel to the nanowire axis. This is a consequence of the nanowire geometry and dielectric mismatch with the environment, and in quite good agreement with the Raman selection rules. We also find a consistent splitting of 1 cm −1 of the E 1 ͑TO͒. The transversal optical mode related to the wurtzite structure, E 2 H , is measured between 254 and 256 cm −1 , depending on the wurtzite content. The azimuthal dependence of E 2 H indicates that the mode is excited with the highest efficiency when the incident and analyzed polarization are perpendicular to the nanowire axis, in agreement with the selection rules. The presence of strain between wurtzite and zinc-blende is analyzed by the relative shift of the E 1 ͑TO͒ and E 2 H modes. Finally, the influence of the surface roughness in the intensity of the longitudinal optical mode on ͕110͖ facets is presented.

show abstract

Section: Methodsmentioning

confidence: 99%

“…49,50 The growth precursors are atomic gallium and As 4 molecules. Gallium forms droplets at the surface and drives the nucleation of the nanowires.…”

Section: Methodsmentioning

confidence: 99%

Raman spectroscopy of wurtzite and zinc-blende GaAs nanowires: Polarization dependence, selection rules, and strain effects

et al. 2009

Self Cite

View full text Add to dashboard Cite

show abstract

“…In order to induce vapor-liquid-solid (VLS) growth of GaAs NWs via Ga droplet catalysts 36,37 , Ga and As fluxes were simultaneously deposited on the substrate surface with the deposition rate of 0.1 and 0.15 ML/s, respectively. The GaAs NWs were grown for 90 min, allowing the formation of the GaAs NWs with ~2 µm-length and ~80 nm in diameter.…”

mentioning

confidence: 99%

Determination of the Optimal Shell Thickness for Self-Catalyzed GaAs/AlGaAs Core–Shell Nanowires on Silicon

et al. 2016

View full text Add to dashboard Cite

We present a set of experimental results identifying various effects that govern the carrier dynamics of self-catalyzed GaAs/AlGaAs core-shell nanowires (NWs) grown by molecular beam epitaxy i.e. surface recombination velocity, surface charge traps, and structural defects.Time-resolved photoluminescence of NW ensemble and spatially-resolved cathodoluminescence of single NWs reveal that emission intensity, decay time and carrier diffusion length of the GaAs NW cores strongly depend on AlGaAs shell thickness but in a non-monotonic fashion. Although 7 nm-AlGaAs shell can efficiently suppress the surface recombination velocity of the GaAs NW cores, the effect of the band bending caused by the surface charges remains dominant if the shell thickness is less than 50 nm; that is, the carrier diffusion length is smaller in the NWs with a thinner shell caused by a stronger carrier scattering at the core/shell interface. If the AlGaAs shell thickness is larger than 50 nm, the luminescence efficiency of the GaAs NW cores starts to be deteriorated,

show abstract

“…The core was obtained by the self-catalysed Ga-assisted process (VLS) [34][35][36][37], with a nominal gallium growth rate of 0.27 μm/h, for 45 min, at T = 630°C and V/III beam equivalent flux ratio of 60. The p-doping was achieved with a beryllium flux corresponding to a doping level of 3.5 × 10 19 atoms/cm 3 for planar growth [38].…”

Section: Nanowire Growthmentioning

confidence: 99%

Electrical contacts to single nanowires: a scalable method allowing multiple devices on a chip. Application to a single nanowire radial p-i-n junction

Heiß

Colombo

Mallorquí

et al. 2013

IJNT

View full text Add to dashboard Cite

Semiconductor nanowires are currently at the forefront of research in the areas of nanoelectronics and energy conversion. In all these studies, realising electrical contacts and statistically relevant measurements is a key issue. We propose a method that enables to contact hundreds of nanowires on a single wafer in an extremely fast electron beam lithography session. The method is applied to nanowire-based radial GaAs p-i-n junction. Currentvoltage characteristics are shown, along with scanning photocurrent mapping.

show abstract

Ga-assisted catalyst-free growth mechanism of GaAs nanowires by molecular beam epitaxy

Cited by 412 publications

References 16 publications

Raman spectroscopy of wurtzite and zinc-blende GaAs nanowires: Polarization dependence, selection rules, and strain effects

Raman spectroscopy of wurtzite and zinc-blende GaAs nanowires: Polarization dependence, selection rules, and strain effects

Determination of the Optimal Shell Thickness for Self-Catalyzed GaAs/AlGaAs Core–Shell Nanowires on Silicon

Electrical contacts to single nanowires: a scalable method allowing multiple devices on a chip. Application to a single nanowire radial p-i-n junction

Contact Info

Product

Resources

About