Comparative study of heavily irradiated silicon and non irradiated SI LEC GaAs detectors

Silicon p+n junctions irradiated with neutron and proton fluences in the range 5x10^11- 4x10^15 cm^(-2) and non-irradiated SI LEC GaAs Schottky barriers have been analyzed. In silicon the concentration Nt of the main radiation-induced deep traps (Et ~0.44- 0 .54 eV) is found to increase proportionally to fluence, achieving values up to 5x10'^15 cm(-3) and a mobility saturation at l00cm^2/Vs has been observed at the highest fluences. A quantitative comparison between heavily irradiated silicon and non-irradiated GaAs evidenced similar charge collection efficiencies, a quasi-intrinsic bulk and similar concentrations of deep defects. On this basis, a unique model, correlating the lattice disorder and the detector performance, is suggested.