Magnetic and optical properties of (Ga1-xMnx)As diluted magnetic semiconductor quantum wires with above room ferromagnetic transition temperature

Scanning electron microscopy and high-resolution transmission electron microscopy measurements showed that the self-assembled (Ga0.8Mn0.2)As quantum wires (QWRs) grown on GaAs (100) substrates by using molecular beam epitaxy were straight crystals. The magnetization curve as functions of the magnetic field at 5 K indicated that the (Ga0.8Mn0.2)As QWRs were ferromagnetic, and the magnetization curve as a function of the temperature showed that the ferromagnetic transition temperature of the (Ga0.8Mn0.2)As diluted magnetic semiconductor (DMS) QWRs was as high as 350 K. Near-field scanning optical microscopy spectra showed the interband transitions of the (Ga0.8Mn0.2)As QWRs, indicative of the Mn atoms acting as substituents. These results indicate that the (Ga1-xMnx)As DMS QWRs with a high Mn concentration hold promise for potential application in spin optoelectric devices operating at room temperature. (c) 2007 American Institute of Physics.