Twinning in GaAs nanowires on patterned GaAs(111)B

Walther, T.; Krysa, A. B.

doi:10.1002/crat.201400166

Cited by 3 publications

(3 citation statements)

References 35 publications

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“…22 Figs 1 and 2). Although not directly stated in that publication, previous publications from that group regarding GaAs NWs in similar conditions, indicate these NWs are ZB with Faceting4041. Once again, the crystalline structure and side-facets are in good agreement with the surface energy prediction by Sibirev and co-workers.…”

Section: Resultssupporting

confidence: 78%

Catalyst shape engineering for anisotropic cross-sectioned nanowire growth

Calahorra

Kelrich

Cohen

et al. 2017

Sci Rep

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The ability to engineer material properties at the nanoscale is a crucial prerequisite for nanotechnology. Hereunder, we suggest and demonstrate a novel approach to realize non-hemispherically shaped nanowire catalysts, subsequently used to grow InP nanowires with a cross section anisotropy ratio of up to 1:1.8. Gold was deposited inside high aspect ratio nanotrenches in a 5 nm thick SiN x selective area mask; inside the growth chamber, upon heating to 455 °C, the thin gold stripes agglomerated, resulting in an ellipsoidal dome (hemiellipsoid). The initial shape of the catalyst was preserved during growth to realize asymmetrically cross-sectioned nanowires. Moreover, the crystalline nature of the nanowire side facets was found to depend on the nano-trench orientation atop the substrate, resulting in hexagonal or octagonal cross-sections when the nano-trenches are aligned or misaligned with the [110] orientation atop a [111]B substrate. These results establish the role of catalyst shape as a unique tool to engineer nanowire growth, potentially allowing further control over its physical properties.For the purpose of controlling and improving semiconducting nanowire (NW) devices for various applications 1-7 , an extensive research effort has been invested in studying NW growth; this was typically achieved by studying the different effects of user controlled parameters: (i) materials -including type and size of NW catalyst, the growth substrates and precursors, and (ii) by altering growth-system parameters, i.e., temperature and precursor flow [8][9][10][11][12][13][14][15][16][17] . In the following report we present a new paradigm, that of catalyst shape engineering, as a useful tool to control NW growth results; in particular, we show that by imposing a non-hemispherical shape to the catalyst-substrate interface, anisotropic cross-sectioned NWs may be grown -NWs with potentially new physical characteristics. Furthermore, we show that the combination of a non-hemispherical catalyst with different crystalline orientations of the long axis results in non-trivial side-faceting of the grown NWs. Nanowire cross section shape and faceting is expected to influence its electrical, mechanical, optical and chemical properties [18][19][20][21][22][23][24] . In particular, Foster et al. have shown that the emission of InGaAs quantum wells embedded inside selective-area-grown anisotropically cross-sectioned GaAs NWs, exhibited linear polarization aligned with the long cross-section axis; basically, when one cross-sectional length-scale is too small to support an optical mode, the spatial degeneracy is lifted and the photoluminescence becomes linearly polarized 22 . This work is an excellent reference for catalyst free growth of anisotropic cross-sectioned NWs, and will be discussed below in further detail. Similar results have been reported by Li et al., in regards to polarisation of laser emission from top-down fabricated GaN NWs 23 . In a different case, Mankin et al. have studied the reactivity of different facets of a VLS ...

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Section: Resultssupporting

confidence: 78%

Catalyst shape engineering for anisotropic cross-sectioned nanowire growth

Calahorra

Kelrich

Cohen

et al. 2017

Sci Rep

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“…2−4 The microfacets lead to sawtooth-like faceting of the sidewall. 5,6 Periodic twinning of ZB nanowires with alternating {111} side facets along the ⟨111⟩ growth direction could occur when enough energy is saved by microfacet formation to compensate for the loss because of twin plane formation.…”

Section: Introductionmentioning

confidence: 99%

“…Straight ZB nanowires grown along the ⟨111⟩ direction are surrounded by six {112} side facets with a hexagonal cross section . The {112} side facets can be replaced by alternating {111} microfacets with lower surface energy. − The microfacets lead to sawtooth-like faceting of the sidewall. , Periodic twinning of ZB nanowires with alternating {111} side facets along the ⟨111⟩ growth direction could occur when enough energy is saved by microfacet formation to compensate for the loss because of twin plane formation.…”

Section: Introductionmentioning

confidence: 99%

Zn₃P₂ Twinning Superlattice Nanowires Grown on Fluorine-Doped Tin Oxide Glass Substrates

2019

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Zn 3 P 2 twinning superlattice nanowires with diameters of 100−300 nm were grown under Sn catalysis on fluorine-doped tin oxide glass by physical vapor transport. The nanowires grew along the [101] direction with nonparallel {101} side facets. The Zn 3 P 2 twinning superlattices had no noticeable crystallographic defects except periodic twin defects. A nonlinear relationship between the twin plane spacing and nanowire diameter was observed. The twin plane formation energy (4.0 × 10 −2 to 4.3 × 10 −2 J/m 2 ) was estimated by fitting the relationship from the nucleation model with a hexagonal nucleus with monolayer height at the triple-phase boundary. The unexpected nonlinear behavior despite the relatively high twin plane formation energy was ascribed to the strong interaction of P atoms dissolved in Sn droplets with the growth interface. P atoms in the droplets may have acted as a surfactant to reduce the liquid−solid surface energy.

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