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Carrier and field dynamics around nanoscale Schottky contacts investigated by ultrafast near-field optics

Achermann, M; Morier-Genoud, F; Seifert, Werner LU ; Wernersson, Lars-Erik LU ; Siegner, U and Keller, U (2002) In Physical Review B (Condensed Matter and Materials Physics) 65(4).
Abstract
We present femtosecond-resolved optical near-field pump-probe measurements of spatiotemporal carrier dynamics around a single nanoscale tungsten (W) disk embedded in GaAs. In these samples, Schottky contacts are formed at the W/GaAs interface. The experimental results are modeled by a selfconsistent treatment of the drift-diffusion equation for the carriers and Poisson's equation for the built-in electric field. At lower optically excited carrier densities, we observe that the built-in field suppresses electron transport towards and trapping into the metal particles. In this regime, an accumulation of carriers is seen at the edge of the depletion region of the Schottky contacts. The calculation reveals that the formation of a self-induced... (More)
We present femtosecond-resolved optical near-field pump-probe measurements of spatiotemporal carrier dynamics around a single nanoscale tungsten (W) disk embedded in GaAs. In these samples, Schottky contacts are formed at the W/GaAs interface. The experimental results are modeled by a selfconsistent treatment of the drift-diffusion equation for the carriers and Poisson's equation for the built-in electric field. At lower optically excited carrier densities, we observe that the built-in field suppresses electron transport towards and trapping into the metal particles. In this regime, an accumulation of carriers is seen at the edge of the depletion region of the Schottky contacts. The calculation reveals that the formation of a self-induced dynamic potential well is the origin of this result. In the high-density regime, efficient carrier transport towards and trapping into the W nanoparticle take place, resulting from the screening of the built-in field. These results allow us to describe measurements of the carrier dynamics in annealed low-temperature grown GaAs and demonstrate that the coupling of the carrier and field dynamics can substantially affect carrier trapping in metal-semiconductor composite materials. (Less)
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author
organization
publishing date
type
Contribution to journal
publication status
published
subject
in
Physical Review B (Condensed Matter and Materials Physics)
volume
65
issue
4
publisher
American Physical Society
external identifiers
  • wos:000173646800064
  • scopus:0037081351
ISSN
1098-0121
DOI
10.1103/PhysRevB.65.045322
language
English
LU publication?
yes
id
196d09e0-d0a1-41ad-940b-e9a677e2daec (old id 343647)
date added to LUP
2007-08-03 11:12:27
date last changed
2017-05-28 04:29:48
@article{196d09e0-d0a1-41ad-940b-e9a677e2daec,
  abstract     = {We present femtosecond-resolved optical near-field pump-probe measurements of spatiotemporal carrier dynamics around a single nanoscale tungsten (W) disk embedded in GaAs. In these samples, Schottky contacts are formed at the W/GaAs interface. The experimental results are modeled by a selfconsistent treatment of the drift-diffusion equation for the carriers and Poisson's equation for the built-in electric field. At lower optically excited carrier densities, we observe that the built-in field suppresses electron transport towards and trapping into the metal particles. In this regime, an accumulation of carriers is seen at the edge of the depletion region of the Schottky contacts. The calculation reveals that the formation of a self-induced dynamic potential well is the origin of this result. In the high-density regime, efficient carrier transport towards and trapping into the W nanoparticle take place, resulting from the screening of the built-in field. These results allow us to describe measurements of the carrier dynamics in annealed low-temperature grown GaAs and demonstrate that the coupling of the carrier and field dynamics can substantially affect carrier trapping in metal-semiconductor composite materials.},
  articleno    = {045322},
  author       = {Achermann, M and Morier-Genoud, F and Seifert, Werner and Wernersson, Lars-Erik and Siegner, U and Keller, U},
  issn         = {1098-0121},
  language     = {eng},
  number       = {4},
  publisher    = {American Physical Society},
  series       = {Physical Review B (Condensed Matter and Materials Physics)},
  title        = {Carrier and field dynamics around nanoscale Schottky contacts investigated by ultrafast near-field optics},
  url          = {http://dx.doi.org/10.1103/PhysRevB.65.045322},
  volume       = {65},
  year         = {2002},
}