Au nanoparticle-decorated silicon pyramids for plasmon-enhanced hot electron near-infrared photodetection

Abstract

The heterojunction between metal and silicon (Si) is an attractive route to extend the response of Si-based photodiodes into the near-infrared (NIR) region, so-called Schottky barrier diodes. Photons absorbed into a metallic nanostructure excite the surface plasmon resonances (SPRs), which can be damped non-radiatively through the creation of hot electrons. Unfortunately, the quantum efficiency of hot electron detectors remains low due to low optical absorption and poor electron injection efficiency. In this study, we propose an efficient and low-cost plasmonic hot electron NIR photodetector based on a Au nanoparticle (Au NP)-decorated Si pyramid Schottky junction. The large-area and lithography-free photodetector is realized by using an anisotropic chemical wet etching and rapid thermal annealing (RTA) of a thin Au film. We experimentally demonstrate that these hot electron detectors have broad photoresponsivity spectra in the NIR region of 1200-1475 nm, with a low dark current on the order of 10 A cm. The observed responsivities enable these devices to be competitive with other reported Si-based NIR hot electron photodetectors using perfectly periodic nanostructures. The improved performance is attributed to the pyramid surface which can enhance light trapping and the localized electric field, and the nano-sized Au NPs which are beneficial for the tunneling of hot electrons. The simple and large-area preparation processes make them suitable for large-scale thermophotovoltaic cell and low-cost NIR detection applications.

Low‐dimensional nanomaterial/Si heterostructure‐based photodetectors

“…By coupling plasmonic nanoparticles with a Si photodetector, it is possible to detect photons with energy below the bandgap of Si. For instance, Wang and coworkers utilized Au nanoparticle‐decorated Si pyramid Schottky junctions to build an efficient plasmonic hot electron photodetector . Such a design successfully extended the response range of a Si photodiode to 1475 nm.…”

“…For instance, Wang and coworkers utilized Au nanoparticle-decorated Si pyramid Schottky junctions to build an efficient plasmonic hot electron photodetector. 43 Such a design successfully extended the response range of a Si photodiode to 1475 nm. In addition, the Schottky junction yielded an extremely low dark current on the order of 10 −5 A cm −2 .…”

Photoelectric Detectors Based on Inorganic p‐Type Semiconductor Materials

“…The process achieves the transformation from light to electronic signals, thus semiconductor materials are considered as the most promising candidates for photodetectors. To date, silicon, one of the most important inorganic semiconductor materials, is routinely used for photodetecting lights at visible and near‐infrared wavelengths, which achieves multibillion‐dollar annual market for digital cameras and other devices . However, the limited absorption range and weak absorbance of silicon greatly restrict the further development and practical application of silicon‐based photodetectors.…”

Porous Ag/TiO2-Schottky-diode based plasmonic hot-electron photodetector with high detectivity and fast response

“…In the past several years, much effort has been focused on improving the performance of photovoltaic hot-electron photodetectors. With the evolution of the plasmonic metal materials from separated nanorods to integrated nanoporous membranes, the responsivity of the Au/Si photovoltaic hotelectron photodetectors has increased from 8 nA/mW to 8.2 μA/mW in the near-infrared region [7,[13][14][15]. However, the detectivity and response time of a photovoltaic hotelectron photodetector, which are of more importance than the responsivity in the applications of optical imaging and optical communication [16], have not improved much.…”