LAUSR

We analyze and compare two complementary 2D plasmonic structures, a gold film perforated with a subwavelength hole array and a periodic lattice of gold disks, for infrared detector applications and argue that the former gives the best results when integrated on top of a Ge/Si quantum dot mid-infrared photodetector (QDIP). The periodicity of both metasurfaces is the same and equal to 1.2 µm. The QDIP coupled with the metal disk array exhibits about 3.7 times plasmonic responsivity enhacement as compared to a conventional Ge/Si device and displays an over 11 times enhacement when integrated with the holey Au film. At 78 K, the quantum efficency of about 2% and photovoltaic peak detectivity of 4.5 × 1012 cm·Hz1/2/W are determined at a wavelength of 4.2 µm in a hybrid QDIP with the perforated gold film.