Reflectance difference spectroscopy of an ultrathin indium arsenide layer on indium phosphide (001)

A model system has been created which allows the surface and bulk contributions to the reflectance difference spectrum to be distinguished. In particular, an indium arsenide film, less than 10 Å thick, has been grown on indium phosphide (001). Reflectance difference spectra of the InAs/InP surfaces were collected and compared to those of InP and InAs. It was found that the InAs/InP heterostructures exhibited electronic transitions between surface states characteristic of InAs (001), while retaining the surface-perturbed bulk transitions characteristic of InP (001). Furthermore, the optical anisotropy arising from the arsenic dimer bonds was shifted 0.2 eV higher for InAs/InP compared to that for InAs. This shift is proportional to 1/a2, where a is the bulk lattice constant.