Te incorporation and activation as n-type dopant in self-catalyzed GaAs nanowires

Research output: Contribution to journalArticle

Abstract

Dopant atoms can be incorporated into nanowires either via the vapor-liquid-solid mechanism through the catalyst droplet or by the vapor-solid growth on the sidewalls. Si is a typical n-type dopant for GaAs, but in nanowires it often suffers from a strongly amphoteric nature in the vapor-liquid-solid process. This issue can be avoided by using Te, which is a promising but less common alternative for n-type doping of GaAs nanowires. Here, we present a detailed investigation of Te-doped self-catalyzed GaAs nanowires. We use several complementary experimental techniques, such as atom probe tomography, off-axis electron holography, micro-Raman spectroscopy, and single-nanowire transport characterization, to assess the Te concentration, the free-electron concentration, and the built-in potential in Te-doped GaAs nanowires. By combing the experimental results with a theoretical model, we show that Te atoms are mainly incorporated by the vapor-liquid-solid process through the Ga droplet, which leads to both axial and radial dopant gradients due to Te diffusion inside the nanowires and competition between axial elongation and radial growth of nanowires. Furthermore, by comparing the free-electron concentration from Raman spectroscopy and the Te-atom concentrations from atom probe tomography, we show that the activation of Te donor atoms is 100% at a doping level of 4×1018cm-3, which is a significant result in terms of future device applications.

Details

Authors
  • Teemu Hakkarainen
  • Marcelo Rizzo Piton
  • Elisabetta Maria Fiordaliso
  • Egor D. Leshchenko
  • Sebastian Koelling
  • Jefferson Bettini
  • Helder Vinicius Avanço Galeti
  • Eero Koivusalo
  • Yara Galvaõ Gobato
  • Ariano De Giovanni Rodrigues
  • Donald Lupo
  • Paul M. Koenraad
  • Edson Roberto Leite
  • Vladimir G. Dubrovskii
  • Mircea Guina
Organisations
External organisations
  • Tampere University of Technology
  • Federal University of São Carlos
  • Technical University of Denmark
  • Eindhoven University of Technology
  • Brazilian Center For Research In Energy And Materials (CNPEM)
  • Radboud University Nijmegen
  • University of Tampere
  • National Research University of Information Technologies
Research areas and keywords

Subject classification (UKÄ) – MANDATORY

  • Condensed Matter Physics
Original languageEnglish
Article number086001
JournalPhysical Review Materials
Volume3
Issue number8
Publication statusPublished - 2019 Aug 5
Publication categoryResearch
Peer-reviewedYes