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Gemini: Germanium mid-infrared plasmonics for sensing

The research leading to the results reported in this website has received funding from the European Union's Seventh Framework Programme under grant agreement n. 613055.

GEMINI aims at laying the foundations of a novel paradigm in optical sensing by introducing molecule-specific strong light-matter interaction at mid-infrared wavelengths through the engineering of plasmonic effects in group-IV semiconductors.

The key enabling technology is the novel germanium-on-silicon material platform: heavily-doped Ge films display plasma frequencies in the mid-infrared range. This allows for the complete substitution of metals with CMOS-compatible semiconductors in plasmonic infrared sensors, with enormous advantages in terms of fabrication quality and costs. Moreover, the mid-infrared range offers the unique opportunity of molecule specificity to target gases in the atmosphere, analytes in a solution or biomolecules in a diagnostic assay.

We will develop sensing substrates containing infrared antennas and waveguides with antenna-enhanced detectors. Antennas and waveguides will be made of heavily-doped Ge to fully exploit plasmonic effects: high field concentration to increase sensitivity, resonant coupling to vibrational lines for chemical specificity, deeper integration to decrease costs. To achieve our goals we will rely on semiconductor growth by chemical vapor deposition, electromagnetic simulations, micro/nanofabrication of devices and advanced infrared spectroscopy. We aim at studying the fundamental properties of new materials and devices in order to assess their potential for sensing.

Impacts of the proposed research go far beyond transforming optical sensing technology. Lab-on-chip disposable biosensors with integrated readout for medical diagnostics would radically cut healthcare costs. The possibility of actively tuning electromagnetic signals by electrical and/or optical control of the plasma frequency in semiconductors holds promises for dramatic opto-electronic integration. Finally, plasmonic semiconductor antennas will impact on photovoltaics, light harvesting and thermal imaging.

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January2017: Here is a summary of the efforts to reach high doping levels for Ge on Si during the three years of GEMINI: active doping concentrations up to 2 1020 cm-3 demonstrated! Full papers reporting the latest achievements due soon...


13 October 2016: great meeting in Milano between the GEMINI consortium and the staff of the INsPIRE ERC Starting Grant cooridnated by Delphine Marris-Morini: we discuss possible collaborations and sinergies in the field of mid-IR photonics with group-IV semiconductors.


In 2016 the results of the second year of the GEMINI project have been presented as oral contributions at the Materials Research Society Spring Meeting, where they have been selected for an invited presentation, Nanospectroscopy 2016, FOTONICA 2016, IRMMW-THz 2016, NFO-14, PLASMONICA 2016, and PRIME 2016.

30 September 2016: the GEMINI consortium meets in Copenhagen, after attending the IRMMW-THz 2016 conference, for the fifth semester meeting. We have great results on Ge doping and waveguide propagation! Ongoing sensing experiments with DNA.

15 August 2016: 'Tunability of the dielectric function of heavily doped germanium thin films for mid-infrared plasmonics' just published on Physical Review B and selected as Editors' Suggestion! A long paper desribing our efforts to understand the dielectric function and the losses of heavily-doped Ge for mid-IR plasmonics.

22 July 2016: 'Optical activation of germanium plasmonic antennas in the mid-infrared' just published on Physical Review Letters! Ultrafast triggering of antenna resonances.

2 February 2016: the GEMINI consortium meets in Roma: two years have already passed by! We discuss the latest results on heavily-doped Ge, DNA sensing and Ge waveguides.

12 October 2015: 'Mid-infrared plasmon-enhanced spectroscopy with germanium antennas on silicon substrates' just accepted for publication on Nano Letters.

23 September 2015: GEMINI participates to the open workshop organized in Roma (IT) by the BILOBA project. The two European FP7 projects will collaborate in the future to organize joint events and workshops.

8-9 September 2015: the GEMINI consortium meets at the University of Konstanz for the third semester meeting. The discussion is focussed on the integration of Ge-based waveguides, antennas, and detectors and on the IR sensing of DNA films.

20-22 April 2015: the GEMINI consortium meets in Brussels for the first review meeting.

February 2015: a paper describing the new paradigms introduced by the GEMINI project in terms of group-IV materials for mid-IR plasmonics is published in the Journal of Nanophotonics.

29-30 September 2014: the whole consortium meets at the University of Glasgow for the first semester meeting. We discuss the promising sensing results obtained with plasmonic germanium antennas: an enhancement of two orders of magnitude has been demonstrated for the sensing of 40 nm PDMS layers, moreover we have successfully exploited the antennas for the sensing of CEMS, a hazardous liquid that can be used to create rudimental explosives. Discussions are also focused on the forthcoming GEMINI activities related to mid-IR integrated detectors and waveguides based on group-IV materials.

Copyright © 2013 L-NESS and Gemini Project

Last updated: 17th October 2016