Optical properties of proton bombarded InP and GaInAsP

The spectral dependence of the optical absorption introduced in InP and GaInAsP by proton bombardment has been measured as a function of dose. A multienergy bombardment schedule was used in order to produce a uniformly bombarded layer 3 μm thick. The induced absorption, which increases nearly linearly with dose, extends well beyond the band edge and decreases nearly exponentially with wavelength over a broad range. A short 420°C anneal reduces this bombardment-induced absorption by more than a factor of ten.