Growth of embedded ErAs nanorods on (411)A and (411)B GaAs by molecular beam epitaxy

The low solubility of Er in GaAs results in the formation of ErAs nanostructures when GaAs is grown with 5-6 at% Er/Ga ratio by molecular beam epitaxy on GaAs surfaces. For growth on the (4 1 1)A GaAs surface, cross-sectional scanning transmission electron microscopy images show the presence of ErAs nanorods embedded in a GaAs matrix extending along the [2 1 1] direction with a spacing of roughly 7 nm and a diameter of roughly 2 nm. Growth on the GaAs (4 1 1)B surface resulted in only nanoparticle formation. Variation of the polarized optical absorption with in-plane polarization angle is consistent with coupling to surface plasmon resonances of the semimetallic nanostructures. (C) 2010 Elsevier B.V. All rights reserved.