Surface plasmon enhanced nanopillar photodetector array

Abstract

We demonstrate surface plasmon-enhaced nanopillar (NP) photodetector arrays in the near IR spectral range. Light coupling into the NPs takes place via surface plasmons through subwavelength, self-aligned metal holes. A novel fabrication technique produces elongated subwavelength holes in the gold top electrode such that the holes are self-aligned to the NPs. Surface plasmons excited on the metal/NP and metal/polymer interfaces couple into the NP resulting in electric field intensity "hot spots". The measured responsivity shows the typical cos ² (θ) dependence with respect to incident light polarization showing the antenna effect of the nanohole array. The shape resonance of the elongated metal hole produces polarization sensitive light absorption1. Surface plasmon enhanced nanopillar detector arrays are a compelling technology for small foot print subwavelength photodetectors.