Impact of Nanograting Phase-Shift on Light AbsorptionEnhancement in Plasmonics-Based Metal-Semiconductor-MetalPhotodetectors

[摘要] The finite difference time-domain (FDTD) method is used to simulate thelight absorption enhancement in a plasmonic metal-semiconductor-metalphotodetector (MSM-PD) structure employing a metal nanograting withphase shifts. The metal fingers of the MSM-PDs are etched atappropriate depths to maximize light absorption through plasmoniceffects into a subwavelength aperture. We also analyse thenano-grating phase shift and groove profiles obtained typically in ourexperiments using focused ion beam milling and atomic force microscopyand discuss the dependency of light absorption enhancement on thenano-gratings phase shift and groove profiles inscribed into MSM-PDs. Our simulation results show that the nano-grating phase shiftblue-shifts the wavelength at which the light absorption enhancement ismaximum, and that the combined effects of the nano-grating grooveshape and phase shift degrade the light absorption enhancement by upto 50%.

[学科分类] 光谱学