Original Article

Citation: Light: Science & Applications (2015) 4, e234; doi:10.1038/lsa.2015.7
Published online 16 January 2015

Integrated colloidal quantum dot photodetectors with color-tunable plasmonic nanofocusing lenses
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Silke L Diedenhofen, Dominik Kufer, Tania Lasanta and Gerasimos Konstantatos

ICFO – Institut de Ciències Fotòniques, Barcelona 08860, Spain

Correspondence: G Konstantatos, ICFO – Institut de Ciències Fotòniques, Av. Carl Friedrich Gauss 3, Mediterranean Technology Park, Castelldefels, Barcelona 08860, Spain. E-mail: gerasimos.konstantatos@icfo.es

Received 14 May 2014; Revised 31 October 2014; Accepted 4 November 2014

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Abstract

High-sensitivity photodetection is at the heart of many optoelectronic applications, including spectroscopy, imaging, surveillance, remote sensing and medical diagnostics. Achieving the highest possible sensitivity for a given photodetector technology requires the development of ultra-small-footprint detectors, as the noise sources scale with the area of the detector. This must be accomplished while sacrificing neither the optically active area of the detector nor its responsivity. Currently, such designs are based on diffraction-limited approaches using optical lenses. Here, we employ a plasmonic flat-lens bull’s eye structure (BES) to concentrate and focus light into a nanoscale colloidal quantum dot (CQD) photodetector. The plasmonic lenses function as nanofocusing resonant structures that simultaneously offer color selectivity and enhanced sensitivity. Herein, we demonstrate the first CQD photodetector with a nanoscale footprint, the optically active area of which is determined by the BES; this detector represents an exciting opportunity for high-sensitivity sensing.

Keywords:

PbS quantum dots; photodetectors; plasmonic bull's eye structures; plasmonic lens