We propose InGaAs nano-photodiodes incorporated with a ring-type polarization-insensitive surface-plasmon (SP) antenna, which consists of gold concentric-ring gratings. This ring antenna induces SP resonance for any polarization of incident light and enhances light absorption in a thin InGaAs layer owing to its symmetric structure. Finite-difference time-domain simulations suggest that the carefully designed ring SP antenna can achieve a quantum efficiency of more than 70% for a wide wavelength range and a maximum efficiency of about 80%. A 3 dB bandwidth of 21 GHz and an external responsivity of 0.39A/W were experimentally demonstrated at a 1.55 μm wavelength.
ASJC Scopus subject areas
- Physics and Astronomy(all)