In situ characterization of nanowire dimensions and growth dynamics by optical reflectance

Magnus Heurlin*, Nicklas Anttu, Christian Camus, Lars Samuelson, Magnus T. Borgström

*Corresponding author for this work

Research output: Contribution to journalArticleScientificpeer-review

39 Citations (Scopus)

Abstract

Optical reflectometry is commonly used as an accurate and noninvasive characterization tool when growing planar semiconductor layers. However, thin-film analysis schemes cannot be directly applied to nanowire systems due to their complex optical response. Here, we report on reliable in situ characterization of nanowire growth with high accuracy using optical reflectance spectra for analysis. The method makes it possible to determine the nanowire length, diameter, and growth rate in situ in real time with high resolution. We demonstrate the methods versatility by using the optical reflectance data for determining nanowire dimensions on both particle-assisted and selective-area grown nanowires. To indicate the full potential of in situ characterization of nanowire synthesis we evaluate the growth dynamics of InP nanowires in the presence of the p-type dopant precursor diethylzinc. We observe that the growth rate is strongly affected by the diethylzinc. At low diethylzinc flows, the growth rate decreases monotonously while higher flows lead to an initially increasing growth rate. From these in situ characterization data, we conclude that the surface migration length of adatom species is affected strongly by the addition of diethylzinc. We believe that this characterization method will become a standard tool for in situ growth monitoring and aid in elucidating the complex growth dynamics often exhibited during nanowire growth.

Original languageEnglish
Pages (from-to)3597-3602
Number of pages6
JournalNano Letters
Volume15
Issue number5
DOIs
Publication statusPublished - 13 May 2015
MoE publication typeA1 Journal article-refereed

Keywords

  • in situ measurement
  • indium phosphide
  • MOVPE
  • nanoimprint lithography
  • nanowire
  • Optical metrology

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