Characterizing Electron-Hole Plasma Dynamics at Different Points in Individual ZnO Rods

Abstract

We have used two-photon emission microscopy to characterize the charge carrier dynamics at different locations within a single ZnO rod. Photoexcitation by a focused laser produces carriers (electrons and holes) in a localized region. Emission is detected using both time-integrated and time-resolved methods. Results show that the electronhole plasma (EHP) state plays a larger role at the end of the rod compared to other points within the structure, where electron-hole recombination proceeds through an excitonic state. The origin of this spatial dependence is attributed to the physical confinement at the end of the structure that prevents an expansion of the photoexcited electron-hole cloud through processes such as carrier diffusion. Whispering gallery modes are identified as contributing to a periodic emission pattern along the length of the structure.

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Document Details

Document Type
Technical Report
Publication Date
Sep 22, 2011
Accession Number
ADA613213

Entities

People

  • Brian P. Mehl
  • James K. Parker
  • John M Papanikolas
  • Joseph A. Puccio
  • Justin R. Kirschbrown
  • Michelle M. Gabriel
  • Ralph L. House

Organizations

  • University of North Carolina at Chapel Hill

Tags

Communities of Interest

  • Energy and Power Technologies

DTIC Thesaurus Topics

  • Band Gaps
  • Charge Carriers
  • Chemistry
  • Electron Holes
  • Electrons
  • Emission Spectra
  • Energy Bands
  • Materials Science
  • Microscopes
  • Microscopy
  • Military Research
  • North Carolina
  • Optical Properties
  • Optics
  • Optomechanics
  • Physical Chemistry
  • Semiconductors

Readers

  • Electrical Engineering
  • Quantum Dot Semiconductor Device Photonics and Graphene Optoelectronic Materials and THz Physics.
  • Theoretical Analysis.

Technology Areas

  • Directed Energy
  • Microelectronics