Hot-Electron-Mediated Ion Diffusion in Semiconductors for Ion-Beam Nanostructuring

Cheng Wei Lee, Andre Schleife

Research output: Contribution to journalArticle

Abstract

Ion-beam-based techniques are widely utilized to synthesize, modify, and characterize materials at the nanoscale, with applications from the semiconductor industry to medicine. Interactions of the beam with the target are fundamentally interesting, as they trigger multilength and time-scale processes that need to be quantitatively understood to achieve nanoscale precision. Here we demonstrate for magnesium oxide, as a testbed semiconductor material, that in a kinetic-energy regime in which electronic effects are usually neglected, a proton beam efficiently excites oxygen-vacancy-related electrons. We quantitatively describe the excited-electron distribution and the emerging ion dynamics using first-principles techniques. Contrary to the common picture of charging the defect, we discover that most of the excited electrons remain locally near the oxygen vacancy. Using these results, we bridge time scales from ultrafast electron dynamics directly after impact to ion diffusion over migration barriers in semiconductors and discover a diffusion mechanism that is mediated by hot electrons. Our quantitative simulations predict that this mechanism strongly depends on the projectile-ion velocity, suggesting the possibility of using it for precise sample manipulation via nanoscale diffusion enhancement in semiconductors with a deep, neutral, intrinsic defect.

Original languageEnglish (US)
Pages (from-to)3939-3947
Number of pages9
JournalNano letters
Volume19
Issue number6
DOIs
StatePublished - Jun 12 2019

Fingerprint

Hot electrons
hot electrons
Ion beams
ion beams
Ions
Semiconductor materials
Electrons
Oxygen vacancies
ions
Magnesium Oxide
Defects
electrons
Proton beams
magnesium oxides
Magnesia
defects
Beam plasma interactions
oxygen
Projectiles
electron distribution

Keywords

  • Multiscale
  • constrained density functional theory
  • enhanced point defect diffusion
  • first principles
  • hot electrons
  • ionizing particle radiation

ASJC Scopus subject areas

  • Bioengineering
  • Chemistry(all)
  • Materials Science(all)
  • Condensed Matter Physics
  • Mechanical Engineering

Cite this

Hot-Electron-Mediated Ion Diffusion in Semiconductors for Ion-Beam Nanostructuring. / Lee, Cheng Wei; Schleife, Andre.

In: Nano letters, Vol. 19, No. 6, 12.06.2019, p. 3939-3947.

Research output: Contribution to journalArticle

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