Theoretical investigation of metal Schottky barrier detector on Si microring resonator

We propose a silicon microring detector for 1. 55 μm wavelength, working at room temperature by means of internal photoemission absorption effect (IPE). To analyze the device, we model the microring waveguide in presence of a thin metal film, using the Z-transform method. Moreover, to calculate the quantum efficiency of the photodetector, we have used the extended analytical model of the IPE for thin metal film based on the Fowler theory. Since the proposed device benefits from both the resonant-cavity-enhanced and waveguide photodetectors; it will enjoy from the high efficiency and wavelength selectivity in a broad spectral range. We also calculate the dependency of efficiency and bandwidth characteristics of the microring based photodiode on the device parameters and coupling conditions. Simulations show that the critical coupling and over coupling conditions are suitable for high efficiency and high speed applications, respectively. Besides, we show that the efficiency of proposed structure is much higher than its resonant-cavity-enhanced photodetector counterparts. The results also show that there is a trade off between the 3dB bandwidth and efficiency of the proposed photodetector.