Vapor-liquid-solid growth of germanium nanostructures on silicon

J. W. Dailey, J. Taraci, I. Clement, David Smith, Jeffery Drucker, S. T. Picraux

Research output: Contribution to journalArticle

98 Scopus citations

Abstract

The pressure and temperature dependencies for vapor-liquid-solid (VLS) growth of Ge nanostructures on Si using chemical vapor deposition are reported. Gold nanodots self-assembled by evaporation on clean hydrogen-terminated and heated Si substrates are used to seed the liquid eutectic VLS growth. Digermane pressures are varied from 4 × 10 -5 to 1 × 10 -2 Torr and substrate temperatures from 400 to 600°C for heteroepitaxial growth on Si(111). Two types of nanostructures are identified, nanowires and nanopillars, with a transition from nanopillar growth to nanowire growth occurring with increasing pressure. Nanowires are characterized by rapid vertical growth, long-aspect-ratio structures, and linear dependence of the growth rate on pressure. At lower pressures a transition to nanopillars is observed; these exhibit both vertical and lateral growth with typical aspect ratios of 1:2. For Si(111) substrates nanowires grow epitaxially with their growth axis along the (111) direction. High-resolution transmission electron microscopy shows that the Ge nanowires are relaxed to their equilibrium lattice spacings a short distance from the Si substrate interface.

Original languageEnglish (US)
Article number12
Pages (from-to)7556-7567
Number of pages12
JournalJournal of Applied Physics
Volume96
Issue number12
DOIs
StatePublished - Dec 15 2004

ASJC Scopus subject areas

  • Physics and Astronomy(all)

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