Magneto-Optical Properties of CuInS2 Nanocrystals.
We compare the absorption, photoluminescence, and magneto-optical properties of colloidal CuInS2 (CIS) nanocrystals with two closely related and well-understood binary analogs: Cu-doped ZnSe nanocrystals and CdSe nanocrystals. In contrast with conventional CdSe, both CIS and Cu-doped ZnSe nanocrystals exhibit a substantial energy separation between emission and absorption peaks (Stokes shift) and a marked asymmetry in the polarization-resolved low-temperature magneto-photoluminescence, both of which point to the role of localized dopant/defect states in the forbidden gap. Surprisingly, we find evidence in CIS nanocrystals of spin-exchange coupling between paramagnetic moments in the nanocrystal and the conduction/valence bands of the host lattice, a behavior also observed in Cu-doped ZnSe nanocrystals, where the copper atoms incorporate as paramagnetic Cu(2+) ions.
†National High Magnetic Field Laboratory, Los Alamos National Laboratory, Los Alamos, New Mexico 87545, United States.
William D
WD
Rice
‡Chemistry Division, Los Alamos National Laboratory, Los Alamos, New Mexico 87545, United States.
Hunter
H
McDaniel
‡Chemistry Division, Los Alamos National Laboratory, Los Alamos, New Mexico 87545, United States.
Victor I
VI
Klimov
†National High Magnetic Field Laboratory, Los Alamos National Laboratory, Los Alamos, New Mexico 87545, United States.
Scott A
SA
Crooker
CuInS2; colloidal nanocrystals; magnetic circular dichroism; magneto-photoluminescence; spin exchange