In situ off-axis electron holography of real-time dopant diffusion in GaAs nanowires

Ganapathi Prabhu Sai Balasubramanian, Elizaveta Lebedkina, Nebile Isik Goktas, Jakob Birkedal Wagner, Ole Hansen, Ray LaPierre, Elizaveta Semenova, Kristian Mølhave, Marco Beleggia, Elisabetta Maria Fiordaliso*

*Corresponding author for this work

Research output: Contribution to journalJournal articleResearchpeer-review

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Abstract

Off-axis electron holography was used to reveal remote doping in GaAs nanowires occurring during in situ annealing in a transmission electron microscope. Dynamic changes to the electrostatic potential caused by carbon dopant diffusion upon annealing were measured across GaAs nanowires with radial p-p+ core-shell junctions. Electrostatic potential profiles were extracted from holographic phase maps and built-in potentials (Vbi ) and depletion layer widths (DLWs) were estimated as function of temperature over 300-873 K. Simulations in absence of remote doping predict a significant increase of Vbi and DLWs with temperature. In contrast, we measured experimentally a nearly constant Vbi and a weak increase of DLWs. Moreover, we observed the appearance of a depression in the potential profile of the core upon annealing. We attribute these deviations from the predicted behavior to carbon diffusion from the shell to the core through the nanowire sidewalls, i.e. to remote doping, becoming significant at 673 K. The DLW in the p and p+ regions are in the 10-30 nm range.

Original languageEnglish
Article number475705
JournalNanotechnology
Volume33
Issue number47
Number of pages9
ISSN0957-4484
DOIs
Publication statusPublished - 2022

Keywords

  • Carbon
  • COMSOL
  • GaAs
  • Nanowire
  • Off-axis electron holography

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