Catalyst free MBE‐VLS growth of GaAs nanowires on (111)Si substrate

Abstract

The behaviour of catalyst free GaAs nanowire growth is investigated on (111)Si substrate by molecular beam epitaxy under different Ga and As fluxes. It is found that the diameter of nanowire is increased by increasing the Ga flux, while it is decreased by increasing the As flux. The growth rate along the wire axis is enhanced by increasing the As flux under a constant Ga flux. Moreover, the Ga droplet at the top disappears by the growth interruption and the growth along the wire axis is strictly prohibited. By adopting the last result, the growth of GaAs/AlGaAs core‐shell structure is attempted. (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)

Gold-free GaAs/GaAsSb heterostructure nanowires grown on silicon

“…% gallium. It shows, in agreement with similar studies by other groups, 3,7 that the liquid gallium droplet is, in our case, the seed particle responsible for the enhancement of axial growth rate in the ͗111͘ direction leading to NW growth, in contrast to selective-area mechanisms reported by the Fukui group in the case of MOVPE grown NW arrays. 8 Having established controlled parameters for gold-free GaAs NW growth on silicon, it is now possible to grow more advanced structures, like core-shell ͓Fig.…”

“…1 However, gold, the most used seed particle for NW growth, is known to create detrimental midgap defects in silicon and should therefore be avoided in Si-compatible technological processes. Recently, the Fukui group 2 and Paek et al 3 reported direct growth on silicon, respectively, of InAs catalyst-free NWs arrays by metalorganic vapor-phase epitaxy ͑MOVPE͒, and self-catalyzed GaAs NWs by molecular beam epitaxy ͑MBE͒, thus opening a viable route for silicon integration of III-V devices. 4 One of the most interesting materials for telecommunication or energy applications is GaAs x Sb 1-x , as its wavelength can be tuned between 0.9 and 1.8 m, and it allows type II band alignments with standard arsenide semiconductors.…”

“…Finally a 1 min AlGaAs shell was grown to passivate the whole structure against nonradiative recombination processes induced at the GaAs surface. 3 Figures 3͑a͒ and 3͑b͒ show the SEM and TEM images of these NWs, along with a three-dimensional simple schematic of the nominal structure. Very interestingly, strain fields are visible in the TEM image only in the regions of the GaAsSb segments, allowing easy identification of these segments at low resolution.…”

MBE growth of self-assisted InAs nanowires on graphene

“…This has attracted quite a bit of attention thanks to the simplicity of the process normally utilizing the most handy/cheap silicon/SiO 2 substrate [10][11][12][13][14]. Si/SiO 2 substrates are successfully used for growth of III-V NWs, in particular GaAs NWs [15][16][17]. Self-assisted InAs NWs typically grow with quite prominent [011] facets [18].…”

Vapor-liquid-solid and vapor-solid growth of self-catalyzed GaAs nanowires

“…[4][5][6] In the case of GaAs, Au-free NW growth has been obtained for selected substrate and growth conditions, with Ga nanoparticles found at the tip of the resulting NWs. [7][8][9][10][11][12][13][14] Using a VLS-like model, NW growth has been associated with the formation of Ga nanoparticles, which promote one-dimensional growth. [7][8][9][10][11][12][13][14] An important general feature of GaAs NWs obtained by Ga-assisted growth is their prevalent zincblende (ZB) crystal structure, 9,10,13,14 in contrast with the wurtzite (WZ) structure commonly observed during Au-catalyzed growth.…”