PLASMONIC NANOSTRUCTURE ENHANCED GRAPHENE-BASED PHOTODETECTORS

ABSTRACT. Graphene exhibits electrical and optical properties promising for future ap-plications in ultra-fast photonics[1]. High carrier mobility and Fermi velocity[2, 3] com-bined with its constant absorption over the visible wavelength range to the near-infrared[4] potentially allow its application for photodetection over a broad wavelength spectrum, op-erating at high frequencies. However, absorption being 2.3 % per monolayer[4], responsiv-ity of these devices is rather low[5, 6]. Here we show that by combining graphene-based photodetectors with metal-nanostructures, plasmonic effects lead to an increased respon-sivity. Graphene is receiving large attention for its peculiar electronic properties and poten-tial use in future electronic devices[7]. However, the field of photonics and optoelec-tronics is largely unexplored and it is speculated that graphene’s real strength lies in this area[1] with applications such as ultra-fast lasing[9] and photodetection[5, 6]. Graphene’s electronic properties such as high carrier mobility and Fermi velocity allow ultra-fast op-erating speeds[2, 3, 10]. Combined with its optical properties such as constant absorp-tion of 2.3 % per monolayer over the visible wavelength range to the near-infrared[4, 11]