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

Amorphous InP layers were produced by ion implantation into semi-insul ating crystalline InP. The absorption coefficient and the refractive i ndex 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 absorpti on coefficient yields an optical gap of about 0.65 eV. The comparison of the spectral dependence of the absorption coefficient of ion implan ted amorphous InP with that of flash evaporated amorphous InP indicate s a higher degree of disorder in the implanted than in the evaporated material.