Room-temperature electron spin dynamics in free-standing ZnO quantum dots.
Conduction band electrons in colloidal ZnO quantum dots have been prepared photochemically and examined by electron paramagnetic resonance spectroscopy. Nanocrystals of 4.6 nm diameter containing single S-shell conduction band electrons have g(*)=1.962 and a room-temperature ensemble spin-dephasing time of T(2)(*)=25 ns, as determined from linewidth analysis. Increasing the electron population leads to increased g(*) and decreased T(2)(*), both associated with formation of P-shell configurations. A clear relationship between T(2)(*) and hyperfine coupling with 67Zn(I=5/2) is observed.
Liu
William K
WK
Department of Chemistry and Center for Nanotechnology, University of Washington, Seattle, Washington 98195, USA.
Whitaker
Kelly M
KM
Smith
Alyssa L
AL
Kittilstved
Kevin R
KR
Robinson
Bruce H
BH
Gamelin
Daniel R
DR
D003102:Colloids / Q000737:chemistry; D004578:Electron Spin Resonance Spectroscopy / Q000379:methods; D004583:Electrons; D009943:Organophosphorus Compounds / Q000737:chemistry; D010084:Oxidation-Reduction; D010777:Photochemistry; D045663:Quantum Dots; D019265:Spectroscopy, Near-Infrared; D013696:Temperature; D015034:Zinc Oxide / Q000737:chemistry*
D003102:Colloids; D009943:Organophosphorus Compounds; C044965:trioctyl phosphine oxide; D015034:Zinc Oxide