Tunable nano-plasmonic photodetectors

TL;DR

This paper demonstrates a scalable, ultra-small plasmonic nanoantenna-based photodetector capable of broadband detection, polarization sensitivity, and electronic switching, promising highly integrable photodetector applications.

Contribution

It introduces a single nanoantenna photodetector design that achieves broadband detection and advanced functionalities at a scale below the resonance wavelength.

Findings

Single nanoantenna detectors enable broadband VIS/NIR detection.

Electrical switching of color sensitivity demonstrated.

Polarization detection achieved with a single nanoantenna.

Abstract

Visible and infrared photons can be detected with a broadband response via the internal photoeffect. By using plasmonic nanostructures, i.e. nanoantennas, wavelength selectivity can be introduced to such detectors through geometry-dependent resonances. Also, additional functionality, like electronic responsivity switching and polarization detection have been realized. However, previous devices consisted of large arrays of nanostructures to achieve detectable photocurrents. Here we show that this concept can be scaled down to a single antenna level, resulting in detector dimensions well below the resonance wavelength of the device. Our design consists of a single electrically-connected plasmonic nanoantenna covered with a wide-bandgap semiconductor allowing broadband photodetection in the VIS/NIR via injection of hot carriers. We demonstrate electrical switching of the color sensitivity as well as polarization detection. Our results hold promise for the realization of ultra small, highly integratable photodetectors with advanced functionality.