Realization of Vertically Aligned, Ultrahigh Aspect Ratio InAsSb Nanowires on Graphite.

E A Anyebe,Q Zhuang,Z M Wang,T D Veal,M K Rajpalke,V Falko,S Hindmarsh,X Chen,F Anderson,A M Sanchez,J Shao,R Sundaram,O Kolosov,B J Robinson

doi:10.1021/acs.nanolett.5b00411

Abstract

The monolithic integration of InAs(1-x)Sb(x) semiconductor nanowires on graphitic substrates holds enormous promise for cost-effective, high-performance, and flexible devices in optoelectronics and high-speed electronics. However, the growth of InAs(1-x)Sb(x) nanowires with high aspect ratio essential for device applications is extremely challenging due to Sb-induced suppression of axial growth and enhancement in radial growth. We report the realization of high quality, vertically aligned, nontapered and ultrahigh aspect ratio InAs(1-x)Sb(x) nanowires with Sb composition (xSb(%)) up to ∼12% grown by indium-droplet assisted molecular beam epitaxy on graphite substrate. Low temperature photoluminescence measurements show that the InAs(1-x)Sb(x) nanowires exhibit bright band-to-band related emission with a distinct redshift as a function of Sb composition providing further confirmation of successful Sb incorporation in as-grown nanowires. This study reveals that the graphite substrate is a more favorable platform for InAs(1-x)Sb(x) nanowires that could lead to hybrid heterostructures possessing potential device applications in optoelectronics.

Highlights

InAs1−xSbx materials have long been recognized as highly suitable candidates for infrared photodetectors since it possess the narrowest bandgap energy among all the III−V semiconductors (0.1 eV at room temperature).[1]
We demonstrate for the first time, the selfcatalyzed growth of ultrahigh aspect ratio (AR) InAs1−xSbx NWs on graphitic substrates (GS)
As-rich conditions and to elucidate the superiority of the graphitic substrate for InAsSb NW growth, we evaluated the morphology of InAs1−xSbx NWs grown on bare Si(111) substrates at identical conditions to that on the GS

Summary

Nano Letters

Materials enable investigation of other important material related properties such as spin−orbit coupling and quantum confinement. Among the NW samples on Si, sample F exhibits the highest AR (inset of Figure 6) it has a relatively high Sb content (xSb(%) = 4%), which is again associated with the H-As condition that favors axial growth This corroborates the observed dependence of NWs AR on As-flux and further confirms that highly As-rich conditions are essential for the suppression of radial growth in favor of enhanced axial growth in InAs1−xSbx NWs. We investigated the percentage of vertically aligned NWs grown on GS as a function of xSb (Figure 5c). Our study elucidates a promising technique for the monolithic integration of InAs1−xSbx NWs on graphitic thin films for high-performance, flexible, and cost-effective optoelectronic devices

Methods

Findings

■ REFERENCES