Optically Detected Magnetic Resonance at 95 GHz of Exciton States in InAs/GaAs Quantum Dots

摘要

We report an optically detected magnetic resonance study of the exciton fine structure in the MBE-grown InAs/GaAs quantum dots (QDs). The ODMR spectra were detected via modulation of the total intensity of the QD emission induced by W-band (95 GHz) microwave excitation. Two spectral features (ODMR signals) are observed when the static magnetic field is either parallel or perpendicular to the growth direction z of the sample. A well-pronounced positive high-field signal observed for B ⊥ z is attributed to hole spin transitions with nonzero (as is the case of quantum wells) effective hole g-factor |gh,⊥| = 3.0. In the case when B ∥ z the high-field signal corresponds to |gh,∥| = 3.9. A strongly anisotropic low-field transition is temptatively attributed to cyclotron resonance (CR).