Self-Seeded Growth of GaAs Nanowires by Metal-Organic Chemical Vapor Deposition

Self-seeded growth of semiconducting nanowires offers significant advantages over foreign metal seeded growth by eliminating seed-associated impurities. However, density and diameter control of self-seeded nanowires has proven Challenging although it is required for integration of nanowires into optoelectronic devices. We report the self-seeded growth of GaAs nanowire arrays on GaAs (111)B, (110), and (111)A substrates by metal organic chemical Vapor deposition. Our approach involves two Steps: the in situ deposition of Ga seed particles and subsequent GaAs nanowire growth. Control of nanowire diameter and array density is achieved :via Ga seed deposition temperature and substrate orientation) increased seed deposition temperatures or changing substrate orientation from (111)A to (110) and (111)B yields reduced areal density and larger nanowire diameters. The density and diameter control approaches could be extended to other self seeded III-V nanowire material systems.