Near-Infrared Sub-Bandgap All-Silicon Photodetectors: State of the Art and Perspectives

Casalino, Maurizio; Coppola, Giuseppe; Iodice, Mario; Rendina, Ivo; Sirleto, L.

doi:10.3390/s101210571

Cited by 159 publications

(85 citation statements)

References 85 publications

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“…Under these conditions, this represents a significant performance improvement compared to prior reports in hotelectron photodetection, 27,28,53 making this platform a viable alternative for other well-established technologies for subbandgap photodetection that are based on internal photoemission, such as metal silicides (Supporting Information section S10). 54 The variation of parameters such as the refractive index of the different PC constituent materials can potentially give access to other spectral regions, such as short-and midwavelength infrared, as an alternative to toxic HgCdTebased photodetection 55 or even to long-wave infrared and THz. 56 Other areas such as photovoltaics or photocatalysis 31 can benefit from this architecture because it bridges the gap between large area, infrared sensitization, and high performance.…”

Section: ■ Resultsmentioning

confidence: 99%

Large-Area Plasmonic-Crystal–Hot-Electron-Based Photodetectors

2015

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In view of their exciting optoelectronic light− matter interaction properties, plasmonic−hot-electron devices have attracted significant attention during the last few years as a novel route for photodetection and light-energy harvesting. Herein we report the use of quasi-3D large-area plasmonic crystals (PC) for hot-electron photodetection, with a tunable response across the visible and near-infrared. The strong interplay between the different PC modes gives access to intense electric fields and hot-carrier generation confined to the metal− semiconductor interface, maximizing injection efficiencies with responsivities up to 70 mA/W. Our approach, compatible with large-scale manufacturing, paves the way for the practical implementation of plasmonic−hot-electron optoelectronic devices. KEYWORDS: hot carriers, plasmonic crystal, photodetectors, soft nanoimprint lithography, internal photoemission T he unique light−matter interaction properties endowed by the plasmonic character of free electrons in metallic nanostructures have motivated vivid research that during the last few decades found applications in a variety of fields such as biology, 1 chemistry, 2 medicine, 3 information theory, and quantum optics 4−6 or energy harvesting and photodetection. 7−9These plasmonic resonances give rise to photocurrent generation by decaying into highly energetic electrons, socalled "hot electrons", which are then emitted from the metal before thermalization and collected at the electrodes on the basis of the principle of internal photoemission. 10,11 The field of hot-electron plasmonics has rapidly developed during the last years, 11−33 led by the interest in active optoelectronic devices with functionalities that emanate from their plasmonic character, such as a tailored spectral response, which are especially appealing for solar-energy harvesting, 11−19 and subband-gap visible or infrared detection.20−27 The increase in hot-electron-based devices has also been fostered by the advances in associated nanofabrication technologies. Electron or ion-beam lithographies are currently used to fabricate prototypes that exploit the spectral tunability of plasmonic architectures. These devices have relied on nanoparticles, 11,22 nanoantennas, 12,20,26 or gratings 24 to excite individually either localized plasmons or surface plasmon polaritons, whose relaxation eventually leads to the creation of hot carriers. This nanostructuring, required to address the spectral tunability in these devices, has hitherto relied on low-throughput, costly, and time-consuming lithographic processes. This may seriously limit the future potential of plasmonic−hot-electron optoelectronics because large-area and high-throughput manufacturing are requisites for energy-harvesting and large-area optoelectronic applications. 34 Here we report the implementation of plasmonic crystals (PC) as a novel platform for hot-electron generation. 35,36 PCs, similar to their dielectric counterparts (photonic crystals), are periodically organized metallic architectur...

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Section: ■ Resultsmentioning

confidence: 99%

Large-Area Plasmonic-Crystal–Hot-Electron-Based Photodetectors

2015

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“…Measurable photoconductivity at energies well below the band gap for the Si reference sample would be produced by transitions involving surface states. 33,34 This feature was expected since the substrates used have high purity and therefore a high carrier lifetime that could be reducing bulk recombination. Transitions involving impurities that produce mid-gap defects are highly unlikely for the same reason.…”

Section: à3mentioning

confidence: 99%

Ruling out the impact of defects on the below band gap photoconductivity of Ti supersaturated Si

Olea

Pastor

Prado

et al. 2013

Journal of Applied Physics

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In this study, we present a structural and optoelectronic characterization of high dose Ti implanted Si subsequently pulsed-laser melted (Ti supersaturated Si). Time-of-flight secondary ion mass spectrometry analysis reveals that the theoretical Mott limit has been surpassed after the laser process and transmission electron microscopy images show a good lattice reconstruction. Optical characterization shows strong sub-band gap absorption related to the high Ti concentration. Photoconductivity measurements show that Ti supersaturated Si presents spectral response orders of magnitude higher than unimplanted Si at energies below the band gap. We conclude that the observed below band gap photoconductivity cannot be attributed to structural defects produced by the fabrication processes and suggest that both absorption coefficient of the new material and lifetime of photoexcited carriers have been enhanced due to the presence of a high Ti concentration. This remarkable result proves that Ti supersaturated Si is a promising material for both infrared detectors and high efficiency photovoltaic devices. V C 2013 AIP Publishing LLC.

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“…In the last years, in order to take advantage of low-cost standard Si-CMOS processing technology, a number of photodetectors have been proposed based on different physical effects, such as: defect-state absorption (Bradley et al, 2005), two photon absorption (TPA) (Liang et al, 2002) and internal photoemission absorption (Zhu et al, 2008a). Physical effects, working principles, main structures reported in literature and the most significant results obtained in recent years were reviewed and discussed in our previous paper (Casalino et al, 2010a). In this paragraph, we go into more depth on photodetectors based on the internal photoemission effect (IPE).…”

Section: Introductionmentioning

confidence: 99%