Homogeneous Array of Nanowire-Embedded Quantum Light Emitters

Makhonin, M. N.; Foster, Andrew P.; Krysa, A. B.; Fry, P. W.; Davies, D. G.; Grange, Thomas; Walther, T.; Skolnick, M. S.; Wilson, L. R.

doi:10.1021/nl303075q

Cited by 41 publications

(48 citation statements)

References 29 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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“…Finally, after a brief growth interrupt, a surface passivating GaAsP cap was grown by addition of phosphine for 10 s, which was maintained during ramping down the growth temperature to room temperature. More details of the growth and optical investigation by photoluminescence can be found in reference [23]. Figure 1 shows such a regular nanowire array at inclined and in top view, observed in a scanning electron microscope with secondary electron detector, demonstrating the achieved uniformity (ß99% site coverage, 3-5 μm length, 138 ± 20 nm diameter, where the ability to measure nanowire length and diameter is mainly limited by the viewing angle and the sampling of 14 nm/pixel in figure 1b, respectively) and the hexagonal cross-section of the nanowires, with {110}-type side facets.…”

Section: Methodsmentioning

confidence: 99%

Twinning in GaAs nanowires on patterned GaAs(111)B

Walther

Krysa

2014

Crystal Research and Technology

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We have studied twinning in GaAs nanowires grown via holes in a silica mask deposited on GaAs(111)B substrates by metal‐organic chemical vapour epitaxy without catalysts. Twins perpendicular to the growth direction form in the nanowires, their {111}‐type side facets leading to corrugation of their {110} side walls. The top facets are almost atomically smooth. Aberration corrected annular dark‐field scanning transmission electron microscopy reveals all twins are rotational, commencing with layers of Ga and finishing with As atoms. Energy‐loss spectroscopic profiling has shown no significant changes in the band‐gap or bulk plasmon energy at those twin boundaries, and the observed reduction of the interface plasmon energy by ∼0.13 eV is close to the detection limit of the technique, reflecting the very low energetic electronic changes related to twin formation.

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“…This flexibility in NW design and growth has enabled novel device applications including NW lasers 10,22,23 , light emitting and detection devices 2,[24][25][26] , ultrahigh density transistors 27 single-electron charging devices 28,29 as well as single photon emitters 15,30,31 and detectors 32 .…”

Section: Introductionmentioning

confidence: 99%