High-speed 1.3 mu m GaInAs detectors fabricated on GaAs substrates

High-speed interdigitated metal-semiconductor-metal detectors have been fabricated on non-lattice-matched, semi-insulating, GaAs substrates using two GaInAs layers of differing indium concentrations to accommodate most of the lattice mismatch by interface misfit dislocations. Bandwidths as high as 3 GHz were measured with none of the detrimental low-frequency gain usually observed in this type of device. This is attributed to the inhibition of the surface trapping of photoinduced carriers by a graded pseudomorphic layer at the surface.<
>