Heterogeneous nucleation of catalyst-free InAs nanowires on silicon

TL;DR

This paper investigates catalyst-free InAs nanowire growth on silicon, demonstrating that substrate sputtering enhances nucleation by creating defect sites, with temperature control reducing parasitic islands and improving nanowire yield.

Contribution

It introduces a method to control nanowire nucleation and density on silicon by sputtering parameters and temperature management, advancing catalyst-free nanowire fabrication techniques.

Findings

Sputtering increases nucleation sites via lattice defects.

Temperature control reduces parasitic island formation.

High nanowire yield achieved with optimized conditions.

Abstract

We report on the heterogeneous nucleation of catalyst-free InAs nanowires on Si (111) substrates by chemical beam epitaxy. We show that nanowire nucleation is enhanced by sputtering the silicon substrate with energetic particles. We argue that particle bombardment introduces lattice defects on the silicon surface that serve as preferential nucleation sites. The formation of these nucleation sites can be controlled by the sputtering parameters, allowing the control of nanowire density in a wide range. Nanowire nucleation is accompanied by unwanted parasitic islands, but by careful choice of annealing and growth temperature allows to strongly reduce the relative density of these islands and to realize samples with high nanowire yield.