Recombination dynamics and screening of the internal electric field in ZnO/ZnxMg1xO multiple quantum wells

C. R. Hall, L. Dao, K. Koike, S. Sasa, H. H. Tan, M. Inoue, M. Yano, P. Hannaford, C. Jagadish, and J. A. Davis
Phys. Rev. B 80, 235316 – Published 15 December 2009

Abstract

We investigate the recombination dynamics within screened c-axis ZnO/Zn0.7Mg0.3O quantum wells using time-resolved photoluminescence and femtosecond pump-probe spectroscopy. The relaxation of excited carriers restores the strength of the internal electric field, which we follow, via the decay time constant, as it increases from 180 ns to 5.8μs. Pump-probe spectroscopy reveals faster, initial decay times of 160–250 ps, which we attribute to additional recombination mechanisms, that become significant for carrier densities greater than 2×1012pairscm2. In addition, the time for screening of the internal electric field to be established is measured to be less than 1 ps. These measurements are followed by a self-consistent calculation which solves the Schrödinger and Poisson equations for pair densities up to 1×1013pairscm2, where there is no further substantial blueshifting of the transition energy with increasing pair density because the electron and hole charge distributions cancel. This calculation fits the measured recombination dynamics and can be used to determine the quantum-well properties at any time following excitation, including carrier densities, transition energies, and recombination lifetimes.

  • Figure
  • Figure
  • Figure
  • Figure
  • Received 29 September 2009

DOI:https://doi.org/10.1103/PhysRevB.80.235316

©2009 American Physical Society

Authors & Affiliations

C. R. Hall1, L. Dao1, K. Koike2, S. Sasa2, H. H. Tan3, M. Inoue2, M. Yano2, P. Hannaford1, C. Jagadish3, and J. A. Davis1

  • 1Centre for Atom Optics and Ultrafast Spectroscopy, Swinburne University of Technology, Melbourne 3122, Australia
  • 2Nanomaterials Microdevices Research Center, Osaka Institute of Technology, Asahi-ku Ohmiya, Osaka 535-8585, Japan
  • 3Department of Electronic Materials Engineering, Research School of Physical Sciences and Engineering, The Australian National University, Canberra, Australian Capital Territory 0200, Australia

Article Text (Subscription Required)

Click to Expand

References (Subscription Required)

Click to Expand
Issue

Vol. 80, Iss. 23 — 15 December 2009

Reuse & Permissions
Access Options
Author publication services for translation and copyediting assistance advertisement

Authorization Required


×
×

Images

×

Sign up to receive regular email alerts from Physical Review B

Log In

Cancel
×

Search


Article Lookup

Paste a citation or DOI

Enter a citation
×