On the development of InAs on GaAs(001) as measured by reflectance anisotropy spectroscopy: continuous and islanded films

Reflectance anisotropy spectroscopy (RAS) has been used to monitor the formation and development of InAs islands grown onto GaAs(001) substrates. It is shown by time resolved measurements that entirely different responses are measured at different photon energies and that these correspond to different aspects of the islanding process. At a photon energy of 2.6 eV RAS is very sensitive to the onset of islanding, whereas the 4.0 eV signal appears to be sensitive to the continuous inter-island film. Using the 4.0 eV signal it was possible to follow the real time development of the islanded surface and to identify that at low growth temperatures, beyond the thickness for islanding, only a small fraction of the incident fluxes are incorporated immediately into the islands.