Excitonic fine structure and recombination dynamics in single-crystalline ZnO


Journal Article

The optical properties of a high quality bulk ZnO, thermally post treated in a forming gas environment are investigated by temperature dependent continuous wave and time-resolved photoluminescence (PL) measurements. Several bound and free exciton transitions along with their first excited states have been observed at low temperatures, with the main neutral-donor-bound exciton peak at 3.3605 eV having a linewidth of 0.7 meV and dominating the PL spectrum at 10 K. This bound exciton transition was visible only below 150 K, whereas the A-free exciton transition at 3.3771 eV persisted up to room temperature. A-free exciton binding energy of 60 meV is obtained from the position of the excited states of the free excitons. Additional intrinsic and extrinsic fine structures such as polariton, two-electron satellites, donor-acceptor pair transitions, and longitudinal optical-phonon replicas have also been observed and investigated in detail. Time-resolved PL measurements at room temperature reveal a biexponential decay behavior with typical decay constants of ∼170 and ∼864 ps for the as-grown sample. Thermal treatment is observed to increase the carrier lifetimes when performed in a forming gas environment.

Full Text

Duke Authors

Cited Authors

  • Teke, A; Özgür, U; Doǧan, S; Gu, X; Morkoç, H; Nemeth, B; Nause, J; Everitt, HO

Published Date

  • November 1, 2004

Published In

Volume / Issue

  • 70 / 19

Start / End Page

  • 1 - 10

International Standard Serial Number (ISSN)

  • 0163-1829

Digital Object Identifier (DOI)

  • 10.1103/PhysRevB.70.195207

Citation Source

  • Scopus