Reflection spectromicroscopy for the design of nanopillar optical antenna detectors

Semiconductor nanowires have proven to be a viable path towards nanoscale photodetectors [1], however the dramatic reduction in semiconductor absorption volume can have a negative effect on responsivity [2]. In order to overcome the reduced absorption volume, incident light must be focused within the nanopillar and surface reflections must be minimized. The ability to lithographically define the position and diameter of individual nanowires makes surface plasmon polariton (SPP) resonances an attractive option, as regular metal scattering centers can overcome the momentum mismatch between the incident wavevector and the SPP mode and scattering center size can influence optical aborption enhancement [3]. In this work we demonstrate a 3-dimensional plasmonic antenna and show enhanced spectral response within the nanopillars.