CMOS-Compatible Broad-Band Hot Carrier Photodetection with Cu–Silicon Nanojunctions

Abstract

Plasmonic harvesting of hot carriers (HCs) in metal−semiconductor (M−S) junctions has stimulated intensive research activities for sub-bandgap photodetection, in particular the development of silicon-based infrared photodetectors. Here, a copper−silicon heterojunction was investigated both theoretically and experimentally in comparison to the commonly used gold− silicon ones. A 1-order-of-magnitude higher responsivity and a longer cutoff wavelength over 2000 nm were observed in experiments in the sub-bandgap wavelength range of silicon with a copper−silicon junction. A phenomenological model was developed to analyze the dynamic processes of HCs and attributed the advanced photodetection performance of copper−silicon devices to the relatively higher electron density of state above the Fermi level and the higher ejection probability. Such a complementary metal−oxide− semiconductor-compatible and low-cost HC photodetection platform shows promising potential in silicon-based optoelectronic applications.

In situ photoelectric biosensing based on ultranarrowband near-infrared plasmonic hot electron photodetection

“…On the one hand, a Schottky junction is formed at the Au/Si interface and the ohmic electrode is formed at the back side of the Si substrate. As a result, interband transition in Si dominates the photoelectric response under illumination with a wavelength smaller than 1100 nm, while the photogenerated HEs, 27 – 33 as shown in Fig. 1(b), become the main contribution factor for the subbandgap photodetection of Si.…”

“…In previous works, Au/Si Schottky PDs demonstrated a broad operating wavelength range from 400 to 2000 nm 27 – 29 On the other hand, wavelength-dependent photodetection is achieved by SPR-modulated light absorption. Although plasmonic antennas, Tamm state, and metasurfaces have been used to tune the photoelectric response, 34 – 36 spectrally selective photodetection was realized in a relatively broad band down to 30 nm with a normalized response bandwidth well above 3%.…”

Plasmonic Nanoneedle Arrays with Enhanced Hot Electron Photodetection for Near‐IR Imaging

“…Although the metal-assisted chemical etching (MACE) method offers a costeffective alternative, the reported works still require sophisticated and costly equipment to form metal catalysts, such as highvacuum coating systems and rapid thermal processing. [5,18,21] Furthermore, the obtained morphology is limited to nanoholes since only silicon under the metal catalysts is etched, which results in insufficient broadband perfect absorption performance and a discontinuous film coating on vertical sidewalls. More importantly, there is a trade-off between maximizing near-field enhancement and minimizing the reflection on the nanostructure, which may limit the generation of energetic carriers.…”

“…[ 1–4 ] Silicon‐based photodetectors possess several advantages, including high stability, compatibility with complementary metal−oxide−semiconductor (CMOS) technology, and low cost. [ 5 ] Despite the benefits, they have a limitation of working in the telecommunication band due to transparency in this regime. [ 6 ] To address this limitation, alternative semiconductors with narrower bandgaps, such as germanium (Ge) and III–V [gallium antimonide (GaSb), indium arsenide (InAs), and gallium arsenide (GaAs)] and II–VI [mercury cadmium telluride (HgCdTe)] materials, have been developed for the NIR regime.…”