Optical properties of AlxGa1-xP (0 <= x <= 0.52) alloys

Abstract

We report optical properties of AlxGa1-xP (0 less than or equal to x less than or equal to 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 E-1, E-0&apos;, E-2, and E-2&apos; critical point energies and their dependence on composition x. (C) 2000 American Institute of Physics. [S0021-8979(00)01003-3].