Surface-plasma-enhanced quantum efficiency of a Ag-Ti-n-GaAs grating photodiode.

An array of Ag-Ti-n-GaAs grating photodiodes was designed and fabricated, with each diode having an active area with a diameter of 400 microm. Both electrical and optical characterizations were performed. We have made two experimental observations concerning (1) the surface-plasma-enhanced detectivity as a function of wavelength for 30 degrees angle of incidence and (2) the offset in angle between the reflectivity minimum and the current maximum at the surface-plasma resonance.