Ultrafast Surface Plasmon III–V Photodetectors Based on Nanomonopoles

A nanoantenna-based plasmonic photodetector is proposed and investigated theoretically. An array of interconnected nanomonopoles on a film of InGaAs on n-doped InP is modeled. The infrared (~1550 nm) responsivity of the structure can reach ~200 mA/W for a 20-nm-thick InGaAs layer. The optimum 3-dB electrical bandwidth of the device is calculated to be ~1 THz for the case of a 20-nm-thick InGaAs layer and a 4 × 4 nanomonopole array. The electrical bandwidth is shown to increase by decreasing the number of elements in the array. A simple linear model for the total resistance of the structure is proposed and validated. The total resistance increases by increasing the thickness of the InGaAs layer and by decreasing the number of array elements.