Tunable Nanoplasmonic Photodetectors

Abstract

Visible and infrared photons can be detected with a broadband response via the internal photoeffect. By use of 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, has 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 visible/near-infrared 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 ultrasmall photodetectors with advanced functionality.

Infrared Surface Plasmons Open a Hole Tunneling Channel in Metal–Oxide–Semiconductor Structures

“…They are damped by the metal surface, into which they decay by creating energetic (nonequilibrium) carriers in the metal, also known as hot electrons and/or hot holes. 1−4 The creation of hot carriers and their manipulation are topics of considerable current interest in plasmonics because they hold the potential of new device physics or opening new chemical reaction pathways, leading to novel applications in photochemistry, 2,5,6 photocatalysis, 7,8 photovoltaic devices, 9 biosensors, 10 and photodetectors on Schottky contacts, 11−14 metal−semiconductor−metal (MSM) structures, 15 and metal−insulator−metal (MIM) structures. 16,17 MIM structures have also been used as optical rectifying tunneling-gap nanoantennas, 18,19 and as electrically driven optical nanoantennas for surface plasmon generation and light emission via inelastic tunneling.…”

“…The creation of hot carriers and their manipulation are topics of considerable current interest in plasmonics because they hold the potential of new device physics or opening new chemical reaction pathways, leading to novel applications in photochemistry, ,, photocatalysis, , photovoltaic devices, biosensors, and photodetectors on Schottky contacts, – metal–semiconductor–metal (MSM) structures, and metal–insulator–metal (MIM) structures. , …”

Plasmonic Field-Guided Patterning of Hybrid Nanostructured Gratings for Their Plasmon-Mediated Optical Activities

“…Plasmon-induced extraordinary optical properties have attracted much research interest in nanophotonics and plasmonics, which provide intriguing applications in optoelectronics, − sensing, photocatalysis, solar energy harvesting, and spectroscopy . Typically, plasmonic nanostructures in the resonant state can concentrate electromagnetic fields at the nanoscale and function as a powerful intermediary to enhance light–matter interactions.…”

Interconnected Dimers with Sub-10 nm Nanogaps by Atomic Layer Deposition for Plasmonic Nanojunctions

“…24 Plasmonic nanorods with electrical contacts can function as photodetectors, light emitters, or new types of photoelectrochemical devices. 19,20,25 Device performance will benefit from the highest electric field enhancements that can be formed in small nanojunctions. Several nanofabrication schemes have been reported for plasmonic dimers, but most do not provide a means for electrical connections or scalability with sub-nm precision.…”

“…Plasmonic nanostructures also absorb light efficiently and may act as nanoscale heaters. − Electric field enhancements are integral to applications of plasmonic materials, and these enhancements are known to be especially strong in nanogaps between closely spaced particles. − Nanogaps act as hot spots where intensified electric fields promote molecular spectroscopy and the generation of hot carriers . In addition to dependence on materials and nanostructure designs, electric field enhancements scale inversely with nanogap sizes, and there has been significant effort to investigate fabrication schemes with sub-nm precision to achieve control over particle spacing. , Nanogaps on the order of 1 nm provide opportunities for new electro-optic devices for light emission, light harvesting, and probing molecules with intense electric fields. − …”