Long catalyst-free InAs nanowires grown on silicon by HVPE

Abstract

We report for the first time on the hydride vapor phase epitaxy (HVPE) growth of long (26 μm) InAs nanowires on Si(111) substrate grown at a standard rate of 50 μm h⁻¹. The nanowires grow vertically along the (111)B direction and exhibit a well faceted hexagonal shape with a constant diameter. The effect of the experimental parameters, growth temperature and III/V ratio, is investigated. The thermodynamic and kinetic mechanisms involved during the growth of such long nanowires are identified. It is demonstrated that growth occurs through direct condensation of InCl and As₄/As₂ gaseous species. Dechlorination of adsorbed InCl molecules is the limiting step at low temperature. Structural analysis through high resolution transmission electron microscopy (HRTEM) and high-angle annular dark-field (HAADF) imaging was performed. The high As₄ partial pressure of the HVPE environment induces the presence of both wurtzite and zinc-blende phases. The results emphasize the potential of the low cost HVPE technique for the monolithic integration of arrays of long InAs nanowires on silicon.