Giant Zeeman effects in colloidal diluted magnetic semiconductor quantum dots with homogeneous dopant speciation

Abstract

Ligand field electronic absorption and magnetic circular dichroism (MCD) spectroscopies are used to probe Co2+ dopant speciation in ZnO, ZnSe, and CdS nanocrystals and confirm the high quality of these colloidal diluted magnetic semiconductor quantum dots (DMS-QDs). Measurements of the QD giant Zeeman splittings using MCD and Zeeman spectroscopies show no enhancement of N0(α−β) relative to bulk. MCD spectroscopy is also presented as an effective method for verifying the successful synthesis of colloidal DMS-QDs when doping cannot be confirmed by ligand field absorption, highly resolved electron paramagnetic resonance, or other rigorous dopant-specific spectroscopic means.