Optical properties of GaAs structures containing a periodic system of layers of AsSb metal nanoinclusions

The optical reflectance and transmittance of GaAs structures grown by molecular-beam epitaxy at a low temperature and periodically delta-doped with antimony or phosphorus are studied. The periodicity of the doping corresponded to the Bragg condition for light with a free-space wavelength of similar to 1.4 mu m. The structures were subjected to annealing at different temperatures in the range from 400 to 760A degrees C. Annealing brings about the formation of a three-dimensional chaotic system of As metal nanoinclusions (quantum dots) inside the GaAs epitaxial layer as well as the formation of two-dimensional layers of AsSb metal nanoinclusions (quantum dots) on the Sb delta layers. The P delta layers have no significant effect on the formation of the system of As nanoinclusions. No features that might be attributed to a disordered three-dimensional system of As nanoinclusions are detected in the optical transmittance and reflectance spectra. The periodic system of two-dimensional layers of AsSb metal nanoinclusions manifests itself as a resonance peak in the optical reflectance and absorption spectra. The resonance reflectance and absorption coefficient increase, as the dimensions of the AsSb nanoinclusions increase. The resonance wavelength depends on the angle of light incidence in accordance with Bragg's law.