Investigation of Indium droplet assisted nucleation of InAs nanowires on graphite

An investigation of the Indium (In) droplet assisted nucleation of InAs nanowires (NWs) on graphite based on the quasi-van-der-Waals epitaxy method is reported. The surface morphology of as-grown NWs was studied using FEI XL30 SFEG scanning electron microscope (SEM) equipped with an energy-dispersive X-ray spectroscopy (EDX) used for composition determination. Clear evidence is presented to demonstrate that the uniaxial growth of the InAs NWs directly on the underlying graphitic substrate is driven by the Indium droplets which etch nanoholes in the graphitic substrate and promote the formation of InAs seed particles underneath the NWs facilitating their vertical directionality. A high yield of InAs NWs exclusively in the [111]/[0001] growth direction on graphite is attributed to the InAs seeding particle. This report not only provides a better understanding of the InAs NWs nucleation on graphite but also unravels a cost-effective technique for obtaining a high yield of vertically oriented NWs on graphite with enormous potential for applications in highly efficient and flexible nano devices.