Tomographic analysis of dilute impurities in semiconductor nanostructures

D. E. Perea, E. Wijaya, J. L. Lensch-Falk, E. R. Hemesath, Lincoln James Lauhon*

*Corresponding author for this work

Research output: Contribution to journalArticle

54 Scopus citations

Abstract

We describe the application of pulsed-laser atom probe (PLAP) tomography to the analysis of dopants and unintentional impurities in Si and Ge nanowires grown by the vapor-liquid-solid mechanism. PLAP tomography was used to determine the concentration of phosphorous in Ge nanowires and B in Si nanowires, enabling comparisons of the atomic concentrations of the reactants with those of the reaction products. Oxygen impurities were also detected, but the contribution from background gas adsorption was not ruled out. Gold catalyst impurities were not detected, and an upper bound of 5 ppm was established. Intrinsic and extrinsic origins of the detection limits of dopants and other impurities are described in detail. A tapered nanowire geometry was found to improve the mass resolution and signal-to-noise ratio by increasing the tip cooling rate. Simulations of nanowire cooling under laser pulsing were used to validate this improved approach to PLAP analysis of nanowires.

Original languageEnglish (US)
Pages (from-to)1642-1649
Number of pages8
JournalJournal of Solid State Chemistry
Volume181
Issue number7
DOIs
StatePublished - Jul 1 2008

Keywords

  • Atom probe
  • Dopants
  • Germanium
  • Impurities
  • Nanowire
  • Semiconductor
  • Silicon

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Ceramics and Composites
  • Condensed Matter Physics
  • Physical and Theoretical Chemistry
  • Inorganic Chemistry
  • Materials Chemistry

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