Plasmonically enhanced tunable spectrally selective NIR and SWIR photodetector based on intercalation doped nanopatterned multilayer graphene (original) (raw)

We present a proof of concept for a spectrally selective near-infrared (NIR) and short-wavelength infrared (SWIR) photodetector based on nanopatterned multilayer graphene intercalated with FeCl3 (NPMLG-FeCl3), enabling large modulation p-doping of graphene. The localized surface plasmons (LSPs) on the graphene sheets in NPMLG-FeCl3 allow for electrostatic tuning of the photodetection in the NIR and SWIR regimes from λ = 1.3 µm to 3 µm, which is out of range for nanopatterned monolayer graphene (NPG). Most importantly, the LSPs along with an optical cavity increase the absorbance from about N × 2.6% for N-layer graphene-FeCl3 (without patterning) to nearly 100% for NPMLG-FeCl3, where the strong absorbance occurs locally inside the graphene sheets only. Our NIR and SWIR detection scheme relies on the photo-thermoelectric effect induced by asymmetric patterning of the multi-layer graphene (MLG) sheets. The LSPs on the nanopatterned side create hot carriers that give rise to Seebeck photodetection at room temperature achieving a responsivity of R = 6.15 × 10 3 V/W, a detectivity of D * = 2.3 × 10 9 Jones, and an ultrafast response time of the order of 100 ns. Our theoretical results pave the way to graphene-based photodetection, optical IR communication, IR color displays, and IR spectroscopy in the NIR, SWIR, mid-wavelength infrared (MWIR), and long-wavelength infrared (LWIR) regimes.