Abstract: An IMSM photodetector structure comprises a GaAs substrate, a buffer region grown on the substrate, an optically active absorbing layer of In.sub.0.42 Ga.sub.0.58 As grown on the absorbing layer. The buffer region includes in sequence a first layer of In.sub.0.23 Ga.sub.0.77 As, an In.sub.0.46 Ga.sub.0.54 As/GaAs superlattice, and a second layer of In.sub.0.23 Ga.sub.0.77 As. An interdigitated pattern of Schottky metal contacts is fabricated on the Al.sub.0.3 Ga.sub.0.7 As/GaAs superlattice. This structure is useful in fabricating long-wavelength, monolithic receivers based on GaAs MESFET technology since the optical and electrical characteristics of the structure are preserved during the thermal annealing cycle necesary in ion-implaned GaAs MESFET processes.

Abstract: Method of diffusing zinc into gallium arsenide and aluminum gallium arsenide. A wafer of gallium arsenide or aluminum gallium arsenide is placed in close proximity to a quantity of granular zinc gallium arsenide. The assemblage is heated in an open-tube furnace in the presence of flowing nitrogen to vaporize zinc whereby zinc diffuses into the gallium arsenide or aluminum gallium arsenide wafer without eroding the surface.