Narrowband photodetection in the near-infrared with a plasmon-induced hot electron device

Abstract

In gratings, incident light can couple strongly to plasmons propagating through periodically spaced slits in a metal film, resulting in a strong, resonant absorption whose frequency is determined by the nanostructure periodicity. When a grating is patterned on a silicon substrate, the absorption response can be combined with plasmon-induced hot electron photocurrent generation. This yields a photodetector with a strongly resonant, narrowband photocurrent response in the infrared, limited at low frequencies by the Schottky barrier, not the bandgap of silicon. Here we report a grating-based hot electron device with significantly larger photocurrent responsivity than previously reported antenna-based geometries. The grating geometry also enables more than three times narrower spectral response than observed for nanoantenna-based devices. This approach opens up the possibility of plasmonic sensors with direct electrical readout, such as an on-chip surface plasmon resonance detector driven at a single wavelength.

Harvesting the loss: surface plasmon-based hot electron photodetection

“…Therefore, hot electron photodetectors based on silicon [44-46, 48, 49, 85-91] can be potentially employed in the telecommunications band, avoiding the need to use InGaAs and Ge detectors. In addition, the tunability of the plasmonic structures enables a straightforward means to tailor the response of a photodetector including the working wavelength, bandwidth, and polarization dependence [44,46,48,49]. For more information on general sub-bandgap photodetection we point the reader to a recent review on the topic [92].…”

“…By tuning the geometry of the plasmonic nanoantenna, one can control the absorption spectrum and therefore the photoresponsivity spectrum. Plasmonic gratings can also be used to realize selective, narrowband hot electron photodetectors [46] ( Figure 2B). The extraordinary optical transmission observed in periodic gratings can strongly couple the freespace light into SPPs, resulting in a strong, narrowband resonant absorption.…”

“…In plasmonic metamaterials, the nonradiative decay process will lead to optical absorption in the metal and reduced performance. Although much effort has been devoted to mitigating plasmon nonradiative decay, recent research has uncovered exciting opportunities for harnessing the process [27,34], such as in photothermal heat generation [35,36], photovoltaic devices [27,37], photocatalysis [38][39][40], driving material phase transitions [41,42], photon energy conversion [43], and photodetection [44][45][46][47][48][49][50]. For instance, the decay of hot electrons can lead to the local heating of the plasmonic nanostructures, making them candidates for nanoscale heat sources [35,36] for use in cancer therapy [51] and solar steam generation [52,53].…”

Molecular interfaces for plasmonic hot electron photovoltaics

“…18,[23][24][25] To this end, metal-semiconductor (MS) Schottky junctions have been employed, 11,12,26 that take advantage of the built-in field in the vicinity of the metal nanostructure to separate the photogenerated carriers. The use of metalinsulator-metal architectures was also successfully employed for hot-electron photodetection.…”

On-Chip Detection of Radiation Guided by Dielectric-Loaded Plasmonic Waveguides

“…The Si-Au interface constituting a Schottky contact has a barrier energy lower than the energy band gap of silicon, and this feature has already been utilized for the realization of Schottky SP-waveguide detector at telecom wavelengths in different configurations 14,15,16 . The use of Schottky contact for the characterization of spectral and/or spatial responses of optical nano-antennas 17,18,19,20 and detection of SP waveguide modes propagating along a metal stripe on a Si substrate 21,22 has also been reported, including the observation of enhancement of the detection efficiency due to surface roughness 23 . In our case, hot charge carriers (holes within the p-type Si substrate) generated by strong electromagnetic fields associated with the excitation of SP modes arrive at the Schottky contact with a kinetic energy exceeding the Schottky barrier height and can thereby be injected into the Si substrate.…”