Annealing of gold nanoparticles on GaP(111)B: Initial stage of GaP nanowire growth

Abstract

GaP(111)B substrate was strewn with 30 nm colloidal Au nanoparticles. Organic residues were removed by: A) boiling in acetone and isopropylalcohol followed by a DI water rinse, B) treatment A + HF:H2O, C) treatment A + O2 plasma for 10 min, 20 min, and 40 min, and D) treatment A combined with O2 plasma (10 min) and HF:H2O. The substrate thus had original 'epi-ready' oxides (A), or fresh native oxides (B and D), or new added oxides (C). The samples were annealed at Ta = 650 °C for 10 min under PH3 and H2 in an MOVPE chamber. This resulted in the growth of GaP stumps along [111]B on each sample. Their length was <3 nm (B and D), ∼20 nm (A), and ∼220 nm (C 40 min). Elemental Ga is left as P2O5/Ga2O3 oxides form on etched GaP(111)B at room temperature. We believe that as the oxides disintegrated during annealing, they released the elemental Ga that combined with phosphorus from PH3, and this led to the growth of the GaP stumps. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.