• Yizhen Ren
  • Philipp Leubner
  • Marcel A. Verheijen
  • Jos E.M. Haverkort
  • Erik P.A.M. Bakkers

We demonstrate the merits of an unexplored precursor, tetrasilane (Si4H10), as compared to disilane (Si2H6) for the growth of defect-free, epitaxial hexagonal silicon (Si). We investigate the growth kinetics of hexagonal Si shells epitaxially around defect-free wurtzite gallium phosphide (GaP) nanowires. Two temperature regimes are identified, representing two different surface reaction mechanisms for both types of precursors. Growth in the low temperature regime (415 °C-600 °C) is rate limited by interaction between the Si surface and the adsorbates, and in the high temperature regime (600 °C-735 °C) by chemisorption. The activation energy of the Si shell growth is 2.4 ±0.2 eV for Si2H6 and 1.5 ±0.1 eV for Si4H10 in the low temperature regime. We observe inverse tapering of the Si shells and explain this phenomenon by a basic diffusion model where the substrate acts as a particle sink. Most importantly, we show that, by using Si4H10 as a precursor instead of Si2H6, non-tapered Si shells can be grown with at least 50 times higher growth rate below 460 °C. The lower growth temperature may help to reduce the incorporation of impurities resulting from the growth of GaP.

Original languageEnglish
Article number295602
Number of pages7
Issue number29
Publication statusPublished - 2019

    Research areas

  • activation energy, core/shell nanowires, hexagonal silicon, higher order silanes, silicon epitaxy

ID: 54238393