Integrated NAno-Detectors for terahertz Applications – NADIA

The challenge consisted in developing i) high speed detectors with wide detection bandwidth for imaging applications and ii) high speed detectors with > 10 GHz modulation bandwidth for wireless communication, modulation being conveyed on the THz carrier. One approach to circumvent the restriction in sensitivity, detection bandwidth and high-speed of THz detectors is to use the progress in InP heterojunction bipolar transistor (HBT) technology, or to use new physical phenomena such as ratchet effect. The required performance improvements of 0.7 µm InP HBTs have been accomplished in the consortium with cut-off frequencies above 350 GHz. To solve the imaging challenge, the reduction of parasitic resistance and capacitance make them an attractive alternative for very wide detection bandwidth detectors. To solve the wireless communications challenge, HBTs used as single easy-to-use THz detectors can be integrated with very high speed robust circuit technology. A few novel ratchet detectors were proposed, most of them have shown good responsivity for frequencies below 300 GHz. The project has investigated in depth the underlying physical phenomena to widen the frequency range of detection.

- High-speed and sensitive InP HBTs THz detectors operating in a large radiation frequency range (0.25–3.1 THz)
- Imaging and tomography validated for HBTs up to 700 GHz
- Wireless communications using HBTs, with modulation bandwidth > 10 GHz & successful THz heterodyne communication with a real-time transmission of an uncompressed HD TV signal at a data rate of 1.5 Gbps with a 300-GHz carrier frequency.
- THz detection & imaging using ratchet cells as detector up to 650 GHz
- Investigation of physical phenomena such as plasmonic effect to widen the frequency range of detection of the ratchet cells.

Des perspectives et suites éventuelles données aux travaux, divers projets ont été envisagés :
- Poursuites des études en détection THz avec fourniture TBH InP III-V Lab:
• Communication sans fil (IES) : avec antennes intégrées et montées sur lentilles Si
• Biocapteurs THz pour l’agronomie (Thèse Région/L2C/IES en cours & Projet I-SITE MUSE soumis par L2C, en cours d’évaluation)
• Biocapteurs pour l’étude de la communication entre protéines (Thèse Région/L2C/IES en cours & IES : projet européen ITN Marie-Curie ITN début 2018)
• Détecteur MMIC (antenne+LNA+détecteur) pour capteurs THz des boîtiers T-Waves technologies
- Projet Européen Soumis
• Infrastructures for co-innovation in TERAhertz, microwave and infrared NOVel detection and imaging using Advanced Electronics (TERA-NOVAE), Research and Innovation Horizon 2020
- Projets transistors et circuits pour applications THz
• Largeur d’émetteur < 0.5µm, fT>750 GHz (projet ANR/FNS ULTIMATE)
• Amplificateurs 350-400 GHz et réseaux d’antennes (projet ANR TERAPACIPODE)

1. D Coquillat , V Nodjiadjim, A Konczykowska, N Dyakonova, C Consejo, et al., Journal of Physics: Conference Series (JPCS), 2015.
2. D Coquillat, A Duhant, M Triki, V Nodjiadjim, A Konczykowska, M Riet, N Dyakonova, O Strauss, W Knap , to be submitted to J. Appl. Physics (2017).
3. I Diouf, S Blin, A Pénarier, P Nouvel, L Varani, D Coquillat, V Nodjadjim, et al., to be submitted to Trans. on THz Sci. and Tech.
7. D Coquillat, V Nodjiadjim, S Blin, A Konczykowska, N Dyakonova, C Consejo, P Nouvel, A Pénarier, J Torres, D But, S Ruffenach, F Teppe, M Riet, A Muraviev, A Gutin, M Shur, W Knap, Int. J.l of High Speed Electronics and Systems 25, 03n04, 1640011 (2016).
11. N Dyakonova, D Coquillat, D But, C Consejo, F Teppe, W Knap, L Varani, S Blin, V Nodjiadjim, A Konczykowska, M Riet, Noise and Fluctuations (ICNF), 2017 International Conference on, IEEE, 1-4 (2017).
13. N Dyakonova, D Coquillat, D But, F Teppe, W Knap, V Nodjiadjim, M Riet, A Konczykowska, P Faltermeier, P Olbrich, S Ganichev, Proc. 42nd IRMMW-THz (Cancun, Mexico), 2017.
14. D Coquillat, V Nodjiadjim, A Duhant, M Triki, O Strauss, A Konczykowska, M Riet, N Dyakonova, W Knap, Proc. 42nd IRMMW-THz (Cancun, Mexico), 2017.
1. I Bisotto, E. Kannan, J. C. Portal, D. Brown, T. Beck, Y. Krupko, L. Jalabert, H. Fujita, Y. Hoshi, Y. Shiraki, T. Saraya, Sci. Technol. Adv. Mater. 15, 045005 (2014).
2. I Bisotto, J-C Portal, D Brown, A Wieck , AIP Advances 5, 117128 (2015).
3. D Coquillat, J Marczewski, P Kopyt, N Dyakonova, B Giffard, W Knap, Optics Express 24, 272 (2016).
4. S Nahar, M Shafee, S Blin, A Pénarier, P Nouvel, D Coquillat, AME Safwa, W Knap, M Hella, The European Physical Journal Applied Physics 76 (2), 20101 (2016).
9. G Auton, D But, J Zhang, E Hill, D Coquillat, C Consejo, P Nouvel, W Knap, L Varani, F Teppe, J Torres, A Song, Nano Letters 17,7015 (2017).

National patent submitted: «Capteur de Rayonnement Electromagnétique», Fr 15 61792, I Bisotto, J-C Portal, 3/12/2015.

Located between the microwave and near-infrared regions of the electromagnetic spectrum, terahertz radiations have many attractive properties for imaging and for wireless data transmission applications. There are presently various devices, operating in the terahertz range, contemplated as basic building blocks of an imaging or a wireless transmission system. These devices are at different research stages, and breakthrough are still needed to reach the application stage.
Terahertz imaging systems have become routine laboratory instruments and have found several niche and industrial applications. Nevertheless up to now, detectors still have relatively low-speed image acquisition.
In parallel, over the past ten years, several groups have considered the prospects of using terahertz radiation as a means to transmit data for future multi-Gbit/s short-range communication systems. Presently, to fulfill the demand for higher data rates the only possibility is to increase the available bandwidth to several tens of gigahertz. This means the carrier frequency must be above 300 GHz. The creation of systems for wireless communication with sub-terahertz and terahertz carrier requires significant improvement of the detectors operating beyond 300 GHz, with high sensitivity and high-speed of operation.
The main idea of the NADIA project is to explore the possibility of high-speed terahertz detectors using semiconductor-based devices. NADIA aims at bringing efficient detection by exploiting the new physical concept of ratchet effect. The spatial asymmetry created by the semi-circular antidot array of the ratchet cell forces electrons under the influence of the terahertz radiation to move preferentially towards the direction of the semi-disc axis. The resulting directed current is the detection signal. Until now a few novel ratchet-effect-based sub-THz detectors based on semiconductor nanostructures were proposed. Most of them have shown good responsivity and Noise Equivalent Power for frequencies below 300 GHz. In this project we will investigate in depth the underlying physical phenomena to widen the frequency range of detection and will tackle another very important characteristic of these devices – their speed. We propose exploration of improvements allowed by integrating these devices with high speed integrated circuits.
Research in high-speed transistors is also driven by various applications, including very high speed/very high spectral efficiency optical transmissions, imaging and high-speed wireless communication, and more generally in the long-term aims at opening up the terahertz gap. Recent advances of InP HBTs with several hundred gigahertz operating frequencies qualify them as key components in such systems, e.g. for amplifier stages, local oscillators, modulation drivers, etc. In that respect, 0.7-µm InP DHBT technology developed in the consortium has demonstrated the best performances to achieve transistors reaching fT beyond 300 GHz and fmax beyond 400 GHz, while keeping the capability of actual medium-complexity circuit fabrication. The main challenge of NADIA for the HBT is to be able to efficiently rectify the alternating potential at the terahertz frequency induced by the incoming radiation into detectable DC photovoltage. One of the possible rectification mechanisms involves rectification by using the nonlinear behavior of the I-V characteristics. Taking advantage of its record bandwidth, InP HBT technology will enable new broadband terahertz detectors that offer also a high breakdown voltage, thanks to superior Johnson figure of merit. In addition, the ability to integrate antennas to efficiently couple the incident terahertz radiation will yield better detector performances.
Finally we will compare the sensitivity, the Noise Equivalent Power, and speed of both ratchet cell and HBT based terahertz detectors.