Analog to digital converters (ADC) are essential components to enhance performance of numerous equipment and systems, for both civilian and military applications. As the sampling rate of electronic ADCs will be particularly capped by sampling signal jitter (100 fs to the state of the art), optical approaches are studied to take advantage of much lower jitter obtained using laser pulses (fs or less). This ADC Poly proposal aims to demonstrate the feasibility of an innovative solution based on the use of an optical deflector, realized by using integrated optics technology. The deflector is the central component of an all-optical ADC that, ultimately, could be capable to sample at a very high rate of 40 Giga samples per second with a resolution of 6 bits or more, which could be then one of the best performances obtained with photonic ADCs. The demonstrator aimed in this project will consist of a deflector, based on an optical leaky waveguide made of electro-optic polymers (EO), capable of addressing a coding mask with 8 resolved lines (3 bits). The leakage angle is controlled by the voltage to be digitized which is applied to the driving electrodes. Active integrated optical components based on EO polymers, modulators for example, usually operate with a microstrip electrode on the EO polymer guide, ensuring an optimal overlap integral between optical and electrical waves. In the case of the deflector, the light leaks from the top of the optical waveguide, making this topology inoperative, so the driving electrode must be located laterally, on both sides of the optical waveguide, and additionally buried, to optimize this overlap. The first challenge of the project is therefore to develop a new technological fabrication process, more complex than those commonly used and to validate the behavior of the EO structure. The buried and laterally placed poling electrodes requested by our design do not allow using the usual poling scheme for chromophores. So, a microwave filter solution is proposed to enable both DC and microwave operation of electrodes. The leaky optical field, distributed along the waveguide, must be collected and focused in the detection plane. The second challenge is then to design an appropriate superstrate over the leaky waveguide as well as micro-optical elements to collect and focus the leaky lightwave. A task is specifically dedicated to the integrated design of the whole structure, optical and microwave parts, of the deflector, as well as the micro-optical components aiming collecting the leakage beam. The fabrication task is divided into several stages. At first, passive waveguides will be made, then phase modulators with the driving electrodes at the same level as the optical waveguide. The characterization of these intermediate components allows to determine the parameters requested for the optimization of the leak waveguide design for the deflector.

Quantum information technologies could lead to breakthroughs in computing/simulation and cryptography. France develops an original platform for quantum information, based on the "Silicon on Insulator" (SOI) technology. Yet many aspects of the physics of silicon quantum bits (qubits) remain poorly understood, which complicates the interpretation of the experiments and the optimization of the devices. The goal of the MAQSi project is to address modeling and simulation of silicon qubits in order to i) make significant progress in the understanding of the physics of these qubits, ii) sort the existing options, and make recommendations for the design of SOI qubits, iii) demonstrate ahead of the experimental work the relevance of SOI technologies for quantum information, and identify their strengths and weaknesses, in order to promote this platform. This project gathers two theoretical groups that have unique capabilities in France on the simulation of quantum silicon devices (INAC/MEM, CNRS/IEMN), with the experimental group that is leader in quantum CMOS measurements and coordinates European projects on the fabrication and measurements of SOI qubits (INAC/PHELIQS). We will set-up tools for the microscopic and atomic scale simulation of silicon qubits and address the following challenges in MAQSi: - Spin manipulation and readout: We intend to achieve fast, all electrical manipulation of electron and hole qubits relying as far as possible on the intrinsic spin-orbit coupling, For that purpose, we need to make progress in the understanding of spin-orbit coupling in silicon, and to optimize the design of the qubits. - Decoherence and variability: We will characterize the disorders that limit the reproducibility (variability) and coherence of silicon qubits. - Two qubit gates: We will investigate exchange coupling between qubits and assess the performances of two (or more) qubit gates. The ambition of MAQSi is to solve these issues through a tight collaboration between experimental and modeling teams, These challenges can not, indeed, be efficiently addressed from an experimental only perspective due to the costs and time scales of device fabrication and characterization. As the quantum information technologies on silicon are developing very fast, it is extremely important to complement the experimental activity with state-of-the-art modeling able to give insights into the operation of silicon qubits and bring forward new ideas.

TRAMP addresses the scientific and technical details of the origin and potential use of the giant piezoresponse observed in silicon nano-objects. After a 10 year debate about the veracity of the giant piezoresistance (PZR) in silicon nanowires, the TRAMP partners (all of whom have been visible participants in this debate) have preliminary evidence for a giant piezocapacitive (PZC) effect. Experiments suggest a central role for stress-induced changes to the charge state of intrinsic defects at the silicon/oxide interface (specifically the Pb0 defect). The capacitive (rather than resistive) nature of the phenomenon is a surprise and the TRAMP partners have the opportunity to be ‘first-in-field’, both in terms of the fundamental science, but also for device applications of this novel phenomenon that occurs in scalable, top-down fabricated silicon nano-objects. In the initial phase of the project, the TRAMP partners will fabricate ohmically contacted, top-down silicon nanomembranes to be tested in a taylor-made apparatus that allows for the frequency and voltage dependence of the piezoresponse to be measured under uniaxial tensile and compressive stresses up to ˜150 MPa. The dependence of the piezoresponse on doping, temperature and nano-object geometry will be explored and then used to improve the design of a second process batch. This method of rapid prototyping has been used previously by the TRAMP partners, and will yield a map of the relative importance of the PZR and PZC responses as a function of these parameters. This is not only essential from the point of view of developing a microscopic understanding of the phenomenon, but also in terms of optimizing conditions for its use as a stress or motion transduction mechanism. Proper characterization of the piezoresponse will employ two techniques specifically adapted to nano-objects: micro-Raman spectroscopy for the measurement of the local stress in nano-objects, with the option to use TERS for the smallest objects, and Laplace current transient spectroscopy for the identification of the electromechanically active defects thought to be responsible for the giant, anomalous piezoresponse. This latter method is not yet widely used but is adapted to defect spectroscopy on any electrically connected nano-objects whose capacitance is too small to permit the use of more traditional capacitive spectroscopies. Once the optimal conditions (i.e. for maximum, stable PZC) have been determined, the TRAMP partners will undertake a technical study of two potential applications: the electrical detection of process induced microstrains in the active layer of ultra-thin commercial silicon-on-insulator wafers for quality control purposes; and as a means to detect motion in a nano-mechanical resonator where standard optical or capacitive methods lose sensitivity. The second application requires the fabrication of in-plane nanoresonators in which the TRAMP partners are expert. In the final task of the project the results of these two technical studies will be used as the basis for discussions with potential industrial partners. Impacts of a successful TRAMP project will therefore include high visible scientific and technical results, the first steps in the characterization of devices exploiting the PZC that are based on a scalable, top-down silicon technology, the patenting of intellectual property, and exploratory talks with partners from the semiconductor manufacturing industry aimed at licensing or collaborative opportunities.

The project aims at growing germanene, the germanium equivalent of graphene, and study the physics of Dirac fermions in this two-dimensional (2D) material. Indeed, germanene departs from conventional 2D electrons systems and graphene by a buckled atomic structure and a significant spin orbit coupling. It should thus form a rich playground for fundamental studies in low-dimensional physics. Based on the expertise recently gained with the growth of germanene on Al(111) by partners of this project, we want to explore the growth of van der Waals heterostructures, consisting of germanene and 2D layered materials, that allow to minimize the interaction between germanene and these supporting materials. For that purpose, our consortium will rely on state of the art in depth characterization tools at the nanoscale: synchrotron radiation, scanning probe microscopy at low temperature with multiple tips and time-resolved spectroscopy capability. Our analysis based on versatile multi-physical characterization will be compared with calculations performed in the framework of the density functional theory, highlighting the impact of the atomic arrangement on the band structure of germanene and how the nature of the substrate might perturb the structural and electronic properties of this remarkable sheet of Ge atoms. Relevant to this project will be the measurement of the Dirac cone hallmark, the band gap, the carrier mobility and the charge transfer from the underlying layer. Also, we will strive to demonstrate the existence of the quantum spin Hall effect, that is expected due to the substantial spin-orbit coupling in germanene. Of particular interest is the study of defects and lattice deformations, that opens the door to topological transitions, like the Kekulé distortion, causing the attachment of mass to Dirac Fermions. Because of the anticipated poor resistance of germanene to ambient conditions, what would severely limit a deeper characterization and prevent its use in spin/opto-electronic applications, efforts will also be devoted to encapsulate germanene. We want to achieve the growth of germanene on Al(111) ultra-thin films on silicon, followed by the removal of the Si parent substrate and the oxidation of the Al layer, and, to protect the top face of germanene with 2D layered materials transferred in ultra-high vacuum. These schemes will take place along with innovations in instrumentations, in particular Raman spectroscopy in ultra-high vacuum that is the tool of choice for fingerprinting 2D materials. French companies that are involved in the Equipex and Labex investment awards of two of the partners will benefit from transfers of know-how in advanced instrumentations. Progress in the field of the synthesis of germanene, in the understanding of the physics of this material and in the design of dedicated tools will be key to turn germanene into practical technologies at the end of the project.

SchoGaN is a four-year proposal for an ambitious research project focused on the use of III-V Nitride materials to achieve GaN Schottky diode and associated frequency multiplier enabling the future development of high power terahertz (THz) frequency sources. The partners of SchoGaN project are three academic laboratories (CNRS-IEMN, CNRS-CRHEA and the LERMA) and a SME (T-Waves Technologies). The consortium brings the required know-how and expertise to achieve significant breakthroughs in the field of frequency multiplier and leading to the realization of high power, tunable, compact, portable, broadband, non-cryogenic THz sources vitally required for many new applications. In this consortium, IEMN and CRHEA bring a strong expertise developed for these last 20 years in III-Nitride technology and material growth, respectively. LERMA brings strong expertise in design, waveguide modelling and fabrication, and assembly of frequency multiplier circuit. T-Waves Technologies will evaluate our THz sources for industrial applications in imaging. The consortium is fully complementary to reach the objectives. It is recognized in our community that the terahertz frequencies range starts at the transition between millimeter and sub-millimeter wave, i.e. 0.3 THz and spreads up to the 10 THz. This large range offers a wide variety of applications: sensing molecules, security, imaging, space science and imaging, non-destructive testing, medical science, very high data rate wireless communications... However, to grow massively, these applications required low cost, compact, portable, reliable and non-cryogenic THz sources and, the most important, of high power level. Today, many technologies are in competition towards low cost and mass-market applications where THz sources are already a vital element. Actually, between the solid state world with the transistor and the optic world with the laser, we note, between 300 GHz and 10 THz, into the famous "THz Gap", that the availability of usable, effective, high power THz sources is tremendously lacking. The objective of the SchoGaN project is to respond to this lack. The only technology that has proven its potentials in the THz range relies on the frequency multiplier principle. The GaAs-based frequency multiplier chains delivers state of the art performance with an output power of 18 µW obtained at 2.58 THz and about 1 mW at 1 THz. However, even if these results are impressive, a large access to these power THz sources remains critical for mass-market applications. Despite the improvements in many technological and design aspects, all solutions cannot overcome the GaAs intrinsic electric field breakdown limitation and the limited thermal conductivity which both represent now the definitive bottlenecks. The search of a candidate exhibiting a high breakdown electric field combined with high thermal conductivity is therefore crucial. This candidate is the Gallium Nitride (GaN). The first bottleneck will be surpassed by its high breakdown electric field, 10 times larger than GaAs. The second bottleneck will be managed thanks to GaN and SiC substrate which present a thermal conductivity 3 and 10 times larger than GaAs, respectively. Both, high breakdown electric field and high thermal conductivity will increase the power handling capabilities of devices resulting in a high output power. It has been shown that the power handling capability of a GaN Schottky diode is almost one order of magnitude larger than its GaAs counterpart. The project addresses THz power sources based on the multiplication chain principle using Gallium Nitride Schottky diode. The signal generation using GaN Schottky diodes is expected to deliver an output power one order of magnitude higher than the current reference. That represents a technological breakthrough towards the next generation of THz sources based on multiplier principle. We target to reach 15 mW of power at 600 GHz, about 10 times the current state of the art.