Light absorption enhancement in metal-semiconductor-metal photodetectors using plasmonic nanostructure gratings

In this paper, we adopt the finite difference time-domain (FDTD) method to optimize the absorption of a novel metal-semiconductor-metal photodetector (MSM-PD) structure based on the use of a double-layer nanostructured metal grating. The metal fingers of the MSM-PDs are etched with appropriate depths to maximize light absorption through plasmonic effects. Simulation results show 40 times enhancement in 980 nm light trapping due to extraordinary optical signal propagation through the nanostructured double-metal grating, in comparison to conventional MSM-PDs.