SUBGAP OPTICAL-PROPERTIES OF AMORPHOUS INP PRODUCED BY ION-IMPLANTATION

Amorphous InP layers were produced by ion implantation into semi-insulating crystalline InP. The absorption coefficient and the refractive index of this amorphous InP were determined in the frequency range 0.2 eV < ($) over bar h omega < 1.3 eV. The refractive index is increased by 20% with respect to the unimplanted substrate. The sub-gap absorption coefficient yields an optical gap of about 0.65 eV. The comparison of the spectral dependence of the absorption coefficient of ion implanted amorphous InP with that of flash evaporated amorphous InP indicates a higher degree of disorder in the implanted than in the evaporated material.