Optical reflectance and electron diffraction studies of molecular-beam-epitaxy growth transients on GaAs(001)

Optical reflectance and reflectance-difference changes resulting from abrupt changes in As and Ga fluences during molecular-beam-epitaxy growth on GaAs(001) are shown to provide surface chemical information, thereby complementing the structural data available from reflection high-energy electron diffraction. Polarization and spectral dependences suggest that the observed optical anisotropies arise from absorption associated with Ga---Ga surface dimer bonds.