Abstract
Recent years have witnessed a growing interest in detectors capable of detecting single 1 photons in the near-infrared (NIR), mainly due to the emergence of new applications such as light 2 detection and ranging (LiDAR) for e.g., autonomous driving. Silicon single-photon avalanche diode 3 is surely one of the most interesting and available technologies, although it yields a low efficiency due 4 to the low absorption coefficient of Si in the NIR. Here, we aim at overcoming this limitation through 5 the integration of complementary metal–oxide–semiconductor (CMOS) -compatible nanostructures 6 on silicon photodetectors. Specifically, we utilize silver grating arrays supporting surface plasmons 7 polaritons (SPPs) to confine superficially the incoming NIR photons and therefore to increase the 8 probability of photons generating an electron-hole pair. First, the plasmonic silver array is geometri- 9 cally designed using time domain simulation software to achieve maximum detector performance 10 at 950 nm. Then, a plasmonic silver array characterized by a pitch of 535 nm, a dot width of 428 nm, 11 and a metal thickness of 110 nm is integrated by means of the focused ion beam technique on the 12 detector. Finally, the integrated detector is electro-optically characterized, demonstrating a QE of 13 13 % at 950 nm, 2.2 times higher than the reference. This result suggests the realization of a silicon 14 device capable of detecting single NIR photons, at a low cost and with compatibility with standard 15 CMOS technology platforms.