High speed and efficient selectively sensitive photodetectors

We report on the resonance cavity MSM-photodiode structures based on nanoscale metallic gratings which are used both as a tool for efficient light confinement and the photocarriers collection. The finger spacing of these detectors is less than the wavelength of incident light. Short collection path along with low diode capacitance (8 fF) allows theoretical cut-off frequencies as high as 500 GHz. Detector has record quantum efficiency of 46% and high selectivity (FWHM=17 nm) at wavelength 790 nm.