GAIN AND DARK CURRENT STUDIES ON PLANAR PHOTODETECTORS MADE ON ANNEALED GAAS-ON-SI

Interdigital, planar photodetectors were fabricated from annealed GaAs /Si heterostructures grown by molecular beam epitaxy using alloyed AuG e/Ni and non-alloyed Cr/Au contacts. The dark current and optical gain of the Cr/Au devices is higher than that of the AuGe/Ni devices. Cont act degradation due to annealing and a p-type background doping consis tently explains our data. The gain-optical power relationship follows a power law with an exponent close to -1.