Self-organized quantum dots of diluted magnetic semiconductors Cd1-xMnxTe

Magneto-optical studies on self-organized quantum dots (QDs) of Cd1-xMnxTe were reported. Cd1-xMnxTe QDs with Mn composition less than 10% were grown successfully on the ZnTe(100) surface by atomic layer epitaxy. A typical do t size of 20 nm in diameter and 2 nm in height and density of the order of 10(11)cm(-2) were confirmed by atomic force microscope (AFM) measurement. I n photoluminescence (PL) measurements on capped QDs, the excitonic emission from Cd1-xMnxTe dots was observed but the spectra were composed of two lin es with a separation of 20-26 meV at low temperatures. In the dependence on the temperature, the excitation intensity and the magnetic field, the PL l ine at the lower-energy side exhibited peculiar behaviors, compared to that in the higher-energy side - rapid quenching with an increase of temperatur e up to 20 K, much smaller Zeeman shift under magnetic fields, and the satu ration of the circular polarization at low magnetic fields. These features of the lower-energy line were discussed in relation to the excitonic magnet ic polaron in QDs. Preliminary results of time-resolved PL and spatial-reso lved PL using the far-field microscope are also shown. (C) 2000 Elsevier Sc ience B.V. All rights reserved.