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

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.