Self-induced growth of vertical free-standing InAs nanowires on Si(111) by molecular beam epitaxy

Abstract

We report self-induced growth of vertically aligned (i.e. along the [111] direction), free-standing InAs nanowires on Si(111) substrates by solid-source molecular beam epitaxy. Implementation of an ultrathin amorphous SiO(x) mask on Si(111) facilitated epitaxial InAs nanowire growth, as confirmed by high-resolution x-ray diffraction 2theta-omega scans and transmission electron microscopy. Depending on growth temperature (in the range of 400-520 degrees C) substantial size variation of both nanowire length and diameter was found under preservation of uniform, non-tapered hexagon-shaped geometries. The majority of InAs nanowires exhibited phase-pure zinc blende crystal structure with few defective regions consisting of stacking faults. Photoluminescence spectroscopy at 20 K revealed peak emission of the InAs nanowires at 0.445 eV, which is approximately 30 meV blueshifted with respect to the emission of the bulk InAs reference due to radial quantum confinement effects. These results show a promising route towards integration of well-aligned, high structural quality InAs-based nanowires with the desired aspect ratio and tailored emission wavelengths on an Si platform.

Position-Controlled Uniform GaAs Nanowires on Silicon using Nanoimprint Lithography

“…The catalyst-free technique has been heavily explored for MOVPE growth of III-V NWs, including GaAs, GaP, InAs and InP [82]. Recently, this technique has also been extended to MBE growth of GaAs [83], InAs [84][85][86][87], InGaAs [88,89], and InAsP [90] NWs.…”

Mobility Enhancement by Sb-mediated Minimisation of Stacking Fault Density in InAs Nanowires Grown on Silicon

“…[12][13][14] Nickel has also been used to catalyze InAs nanowire growth on silicon 15 but these nanowires are not functional for direct integration as they grow following random orientations with respect to the substrate. There have therefore been many reports of nanowire growth without the use of heterocatalytic nanoparticle seeds [16][17][18][19][20][21] . In the case of the widely-studied narrow-bandgap semiconductor InAs, however, the absence of a heterocatalyst results in the nanowires displaying very high densities of defects including stacking faults, twin boundaries and polytypism, i.e.…”

Influence of growth parameters on In-droplet-assisted growth of InAs nanowires on silicon

“…The highest yield of vertically aligned NWs was obtained at *450°C, while a minimum temperature of *420°C is required for NWs nucleation on bare Si substrate. This demonstrates that the temperature domain for the nucleation of In-catalyzed InAs NWs on bare Si ranges from 420 to 475°C, which is slightly narrow when compared to that of MBE (Koblmüller et al 2010) grown, catalyst-free InAs NWs on SiO 2 /Si (111) substrates (*400-500°C). Figure 2a shows a plot of NWs length (L NW ) and diameter (D NW ) as a function of G T .…”

“…Various growth strategies have been employed for the growth parameter studies of InAs NWs including selective area growth (SAG) (Mandl et al 2011;Bjoerk et al 2012), catalyst-free growth on SiO x -coated substrates Koblmüller et al 2010;Madsen et al 2011), and Au-catalyzed growth (Dayeh et al 2007;Tchernycheva et al 2007;Babu and Yoh 2011;Zhang et al 2016). An investigation of the influence of growth parameters on In-droplet-assisted InAs NWs grown on Si would unravel the conditions for realizing optimal NWs with the highest density and aspect ratio as well as enable for the predictable and reproducible fabrication of high performance, and impurity-free nanoelectronic devices compatible with the CMOS technology.…”

“…However, despite the significant influence of In-rich conditions (and in effect the predeposition of In droplets) on the NWs geometry (Jung et al 2014;Zhang et al 2014) resulting from strong differences in adatom kinetics compared to other growth techniques, little is known about the influence of growth parameters on the morphology and yield of In-catalyzed InAs NWs with the few available reports limited to metal organic chemical vapor deposition (MOCVD) growth on GaAs (Forbes et al 2010) and InP (Zhang et al 2013) substrates. Given the significant differences (Cho and Arthur 1975;Finnie and Homma 1999;Arthur 2002;Dubrovskii et al 2005;Koblmüller et al 2010) between MOCVD and MBE, it is essential to undertake a growth parameter study of MBE grown In-droplet-assisted InAs NWs on Si. More so, the control of the morphology and yield of InAs NWs directly grown on Si substrates as a function of growth parameters via an In-assisted technique is yet to be explored despite its enormous potential for the impurity-free integration of III-V NWs on Si, which is, however, not surprising given the very limited report of Incatalyzed InAs NWs growth directly on bare Si (Anyebe et al 2014).…”