Silicon Photodetectors Based on Internal Photoemission Effect: The Challenge of Detecting Near-Infrared Light

Casalino, Maurizio; Sirleto, L.; Iodice, Mario; Coppol, Giuseppe

doi:10.5772/36014

Cited by 7 publications

(7 citation statements)

References 32 publications

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“…The Au/SiNH device containing the thinnest plasmonic coating layer (i.e., the 20 nm case) has a C F value of 0.12, higher than the other two cases. This finding provides clear evidence that thinning down the thickness of plasmonic absorber can efficiently improve the probability of hot electron ejection, regarding on the finite mean free path of the electrons in metals. , As illustrated in the inset of Figure c, we observed an IQE approaching 1.7% at the band edge of silicon, which is much higher than the values reported by previous antennas or grating-Schottky photodetector in the wavelength region where silicon does not absorb. , Apart from the dependency of IQE on the thickness, the impact of the spatial distribution of the plasmonic absorption is also critical. This is already apparent when comparing the responsivity of the planar reference with the Au/SiNH devices.…”

Section: Spectral Responsivity Of the Hot Electron Conversionsupporting

confidence: 56%

“…Unfortunately, carrier transport and ejection in metals are relatively unefficient processes compared to semiconductor materials, manifesting in previously reported ultralow IQE especially for NIR wavelengths (less than 1%). , As a consequence, the photon-to-electricity efficiency of hot electron devices relies more heavily on their electrical design. Since the mean free path of hot electron in metal in only several to several tens nanometers, , it has been reported that the plasmonic resonance with high field localization (i.e., hot spots) adjacent to the barrier of MS or MIM can significantly increase the collection possibility of hot electrons . Furthermore, it is possible to gain IQE enhancement with shortened transporting path of energetic carriers by straightforwardly thinning down the thickness of plasmonic absorber layer. , Concerning the importance of hot electron extraction, a framework for systematically analyzing the impacts of hot spots control and plasmonic absorber thickness is needed.…”

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confidence: 99%

“…9,12 As a consequence, the photon-to-electricity efficiency of hot electron devices relies more heavily on their electrical design. Since the mean free path of hot electron in metal in only several to several tens nanometers, 21,22 it has been reported that the plasmonic resonance with high field localization (i.e., hot spots) adjacent to the barrier of MS or MIM can significantly increase the collection possibility of hot electrons. 12 Furthermore, it is possible to gain IQE enhancement with shortened transporting path of energetic carriers by straightforwardly thinning down the thickness of plasmonic absorber layer.…”

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confidence: 99%

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Hot Electron Harvesting via Photoelectric Ejection and Photothermal Heat Relaxation in Hotspots-Enriched Plasmonic/Photonic Disordered Nanocomposites

Wen

Chen

et al. 2017

ACS Photonics

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The ability of plasmonic nanostructures to harvest photons beyond the traditional band-to-band photovoltaic conversion of semiconductors has stimulated intensive research activities in hot electron. As an emerging strategy for energyharvesting, photodetection and photocatalysis, realization of broadband and efficient plasmonic absorption with easily constructed metal-semconductor (M-S) nanosystems is essential for improving its photoelectric efficiency, while minimizing the cost and complexity of fabrication. Here, we report an approach for near-infrared (NIR) photodetection by combining the randomly and densely packed photonic nanostructures with ultrathin plasmonic coatings. Relying on the Au covered disordered silicon nanoholes (SiNHs) M-S platform, the efficient plasmonic absorption, strong field localization and together with random nature facilitate the broadband photon-energy conversion from both photoelectric hot electron ejection and photothermal hot electron relaxation. Spectral-and time-resolved studies reveal that the proposed Au-SiNHs device is capable of tracking fastvarying NIR signals via hot electron emission process, with a photoresponsivity around 1.5−13 mA/W at wavelengths ranging from 1100 to 1500 nm. With a detailed theoretical analysis based on phenomenological model, different loss mechanisms involved in the hot electron related photoelectric process were described quantitatively and a large improvement potential was identified in the proposed hot electron harvesting platform. In addition, we demonstrated that the closely distributed random voids and tips in the Au-SiNHs structures enable the formation of a substantial amount of hot-spots that can significantly elevate the local temperature through the relaxation of the nonejected hot electrons and, therefore, generate the obvious photothemal mediated photoresponse under voltage driven conditions.

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Section: Spectral Responsivity Of the Hot Electron Conversionsupporting

confidence: 56%

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confidence: 99%

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confidence: 99%

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Hot Electron Harvesting via Photoelectric Ejection and Photothermal Heat Relaxation in Hotspots-Enriched Plasmonic/Photonic Disordered Nanocomposites

Wen

Chen

et al. 2017

ACS Photonics

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“…E xtracting energetic carriers from light absorption in socalled hot carrier Schottky barrier (SB) junctions has attracted enormous attention, as it allows harvesting low photon energies that have so far been omitted from semiconductor photodetectors. 1−8 Since metals offer zero bandgap energy, their operation can in principle cover visible, mid-infrared, terahertz, and microwave regimes, which holds great promises for gas detection, 9,10 imaging sensors, 11 wavelength determination, 12,13 power monitoring, 14 and sustainable power supplies. 15−17 Taking silicon photodetectors (with a bandgap energy of 1.1 eV) 18 for instance, exploitation of SB devices can result in a highly integrated CMOScompatible and inexpensive alternative to commercially used germanium (Ge) and gallium arsenide (GaAs) photodetectors at telecommunication wavelengths.…”

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confidence: 99%

TiO_2–x-Enhanced IR Hot Carrier Based Photodetection in Metal Thin Film–Si Junctions

Güsken

Lauri

et al. 2019

ACS Photonics

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We investigate titanium nitride (TiN) thin film coatings on silicon for CMOS-compatible sub-bandgap charge separation upon incident illumination, which is a key feature in the vast field of on-chip photodetection and related integrated photonic devices. Titanium nitride of tunable oxidation distributions serves as an adjustable broadband light absorber with high mechanical robustness and strong chemical resistivity. Backside-illuminated TiN on p-type Si (pSi) constitutes a self-powered and refractory alternative for photodetection, providing a photoresponsivity of about ∼1 mA/W at 1250 nm and zero bias while outperforming conventional metal coatings such as gold (Au). Our study discloses that the enhanced photoresponse of TiN/pSi in the near-infrared spectral range is directly linked to trap states in an ultrathin TiO2–x interfacial interlayer that forms between TiN and Si. We show that a pSi substrate in conjunction with a few nanometer thick amorphous TiO2–x film can serve as a platform for photocurrent enhancement of various other metals such as Au and Ti. Moreover, the photoresponse of Au on a TiO2–x /pSi platform can be increased to about 4 mA/W under 0.45 V reverse bias at 1250 nm, allowing for controlled photoswitching. A clear deviation from the typically assumed Fowler-like response is observed, and an alternative mechanism is proposed to account for the metal/semiconductor TiO2–x interlayer, capable of facilitating hole transport.

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“…Indeed, IPEbased PDs are very fast thanks to the unipolar nature of the Schottky junction, and they have already shown the capability to be monolithically integrated with Si-based charge coupled devices for infrared applications [24]. IPE-based Si PDs were already summarized in a previous work of some years ago [25].…”

Section: Introductionmentioning

confidence: 99%

Recent Advances in Silicon Photodetectors Based on the Internal Photoemission Effect

Casalino¹

2017

New Research on Silicon - Structure, Properties, Technology

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Silicon technologies provide an excellent platform in order to realize microsystems where photonic and microelectronic functionalities are monolithically integrated on the same substrate. In recent years, a lot of passive and active silicon photonic devices have been optimized to work at telecom wavelengths where, unfortunately, silicon has a neglectable optical absorption due to its bandgap of 1.12 eV. Although silicon cannot detect wavelengths above 1.1 μm, in recent years, tremendous advances have been made in order to make it suitable for operation in the near-infrared spectrum. One of the approaches is to take advantage of the internal photoemission effect through a Schottky junction where a metal absorbs the incoming radiation and emits hot carriers into silicon making sub-bandgap detection possible. The present chapter describes the more recent advances in the field of the silicon photodetectors based on the internal photoemission effect showing as devices based on new emerging materials and complex nanostructure are leading this family of device to compare favorably with the well-established technologies commonly used for telecom wavelengths based on germanium and III-V semiconductors.

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Silicon Photodetectors Based on Internal Photoemission Effect: The Challenge of Detecting Near-Infrared Light

Cited by 7 publications

References 32 publications

Hot Electron Harvesting via Photoelectric Ejection and Photothermal Heat Relaxation in Hotspots-Enriched Plasmonic/Photonic Disordered Nanocomposites

Hot Electron Harvesting via Photoelectric Ejection and Photothermal Heat Relaxation in Hotspots-Enriched Plasmonic/Photonic Disordered Nanocomposites

TiO_2–x-Enhanced IR Hot Carrier Based Photodetection in Metal Thin Film–Si Junctions

Recent Advances in Silicon Photodetectors Based on the Internal Photoemission Effect

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Silicon Photodetectors Based on Internal Photoemission Effect: The Challenge of Detecting Near-Infrared Light

Cited by 7 publications

References 32 publications

Hot Electron Harvesting via Photoelectric Ejection and Photothermal Heat Relaxation in Hotspots-Enriched Plasmonic/Photonic Disordered Nanocomposites

Hot Electron Harvesting via Photoelectric Ejection and Photothermal Heat Relaxation in Hotspots-Enriched Plasmonic/Photonic Disordered Nanocomposites

TiO2–x-Enhanced IR Hot Carrier Based Photodetection in Metal Thin Film–Si Junctions

Recent Advances in Silicon Photodetectors Based on the Internal Photoemission Effect

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TiO_2–x-Enhanced IR Hot Carrier Based Photodetection in Metal Thin Film–Si Junctions