Optical properties of AlxGa1−xP (0⩽x⩽0.52) alloys

Abstract

We report optical properties of AlxGa1−xP (0⩽x⩽0.52) alloys grown by gas source molecular-beam epitaxy on S-doped GaP(001) substrates. Room-temperature pseudodielectric function spectra from 1.5 to 6.0 eV were obtained by spectroscopic ellipsometry. By applying the parabolic-band critical point model to numerically calculated second energy derivatives of these spectra, we obtained accurate room-temperature values of the E1, E0′, E2, and E2′ critical point energies and their dependence on composition x.