Periodic Reporting for period 1 - NEUCODES (Neuro-encoded electronic skin)
Période du rapport: 2023-09-18 au 2025-12-17
The NEUCODES project aims to realise neuro-encoded electronic skin that can convert the tactile sensing signal (analogue signal) into biological spike trains. By doing so, the electronic skin will “speak the same language” as the human skin, enabling a smooth communication between the two. Such tactile signal encoding is also expected to serve as the first step towards achieving human-level tactile sensation. With hundreds of thousands of mechanoreceptors distributed all over the skin, the amount of tactile data generated in real time is significant. The highly distributed and hierarchical data handling strategy, including the sensory data encoding targeted here, serves as an effective approach in downscaling the large volume of the tactile sensory data, before they are transmitted to the next perceptual level. This will notably decrease the data latency and power consumption involved in the whole process.
The project will have a notable scientific impact by advancing several relevant domains including flexible and printed electronics, neuroscience, and robotics, and foster the fusion of knowledge. The project will also have a societal impact by neuroprosthetics that restores their tactile sensation from the neurological level, greatly improving the quality of life of those patients suffering from diseases such as peripheral neuropathy. The project will also have a medium- to long-term economic impact by enabling competitive edge to European companies in the field of robotics, neuroprosthetics and flexible electronics – all of which will address a dynamic and fast-growing sector with macro-economic impact, leading to innovation-based growth. For example, neuroprosthetics market alone will reach a market of 15 billion worldwide by 2025. The demonstrated technology will potentially lead to spin-out companies and create new jobs.
The project will have a notable scientific impact by advancing several relevant domains including flexible and printed electronics, neuroscience, and robotics, and foster the fusion of knowledge. The project will also have a societal impact by neuroprosthetics that restores their tactile sensation from the neurological level, greatly improving the quality of life of those patients suffering from diseases such as peripheral neuropathy. The project will also have a medium- to long-term economic impact by enabling competitive edge to European companies in the field of robotics, neuroprosthetics and flexible electronics – all of which will address a dynamic and fast-growing sector with macro-economic impact, leading to innovation-based growth. For example, neuroprosthetics market alone will reach a market of 15 billion worldwide by 2025. The demonstrated technology will potentially lead to spin-out companies and create new jobs.
The fellow has worked at the Northeastern University in Boston, USA and University of Sheffield, Sheffield, UK during the outgoing phase of the fellowship. At Northeastern University, the fellow focused on both experimental and simulation studies. At the experimental front, the fellow performed nanowire synthesis, its contact printing, transistor fabrication using printed nanowires, interconnecting the transistors, selective doping of nanowire channel, and eventually the circuit (inverter) realisation. The fellow has characterised the transistors and inverter circuits based on nanowire ensembles, systematically compared their performance, and optimised the whole fabrication process. Particularly, the bottom-gated nanowire transistor exhibits synaptic behaviour, which mimics the response of the biological synapse including long- and short-term potentiation and depression, spiking rate dependent plasticity, etc.
At the simulation front, the fellow has built a Monte Carlo simulation framework to quantify the stochasticity of the nanowire ensemble-based transistors. The fellow also has developed a mathematical equation set to describe the synaptic behaviours observed from the bottom-gated nanowire-based transistors. Using the equations, the fellow has developed a SPICE simulation framework that allows the simulation of transistor and circuit behaviours which can serve as biomimetic mechanoreceptors. At the University of Sheffield, the fellow built on the TouchSim model developed in the Active Touch Lab [1] and interfaced it with the SPICE simulation, enabling the simulation of touch in the electronic skin context.
The main achievements are:
1) Developed the fabrication scheme to fabricate ZnO nanowire ensemble-based transistors and circuits controlled by localised bottom gate.
2) Characterised the nanowire-ensemble based transistors and inverters, and explored their synaptic behaviours.
3) Built a theoretical framework to simulate the touch process in electronic skin.
[1] Saal, H. P., Delhaye, B. P., Rayhaun, B. C., & Bensmaia, S. J. Simulating tactile signals from the whole hand with millisecond precision. Proceedings of the National Academy of Sciences, 114(28), E5693-E5702, 2017.
At the simulation front, the fellow has built a Monte Carlo simulation framework to quantify the stochasticity of the nanowire ensemble-based transistors. The fellow also has developed a mathematical equation set to describe the synaptic behaviours observed from the bottom-gated nanowire-based transistors. Using the equations, the fellow has developed a SPICE simulation framework that allows the simulation of transistor and circuit behaviours which can serve as biomimetic mechanoreceptors. At the University of Sheffield, the fellow built on the TouchSim model developed in the Active Touch Lab [1] and interfaced it with the SPICE simulation, enabling the simulation of touch in the electronic skin context.
The main achievements are:
1) Developed the fabrication scheme to fabricate ZnO nanowire ensemble-based transistors and circuits controlled by localised bottom gate.
2) Characterised the nanowire-ensemble based transistors and inverters, and explored their synaptic behaviours.
3) Built a theoretical framework to simulate the touch process in electronic skin.
[1] Saal, H. P., Delhaye, B. P., Rayhaun, B. C., & Bensmaia, S. J. Simulating tactile signals from the whole hand with millisecond precision. Proceedings of the National Academy of Sciences, 114(28), E5693-E5702, 2017.
1. The fellow has developed a novel fabrication process scheme to realise large-scale, ZnO nanowire ensemble-based transistors, individually controlled by localised bottom gate. The achieved figure of merits is 5.89±5.16 µA for on-state current, 0.44±1.36 V for threshold voltage, 556±543 mV/dec for subthreshold slope. These are the best metrics comparing to the prior arts as shown in the figure inserted below.
Potential impact: this lays the foundation for realising large-scale electronics using printed nanowire ensembles. Nevertheless, extra optimisation in nanowire synthesis is needed to further improve the uniformity of the transistors.
2. Developed the mathematical equation sets to describe the synaptic behaviour from bottom-gated, nanowire transistor. This is the first proposed mathematical model of its kind.
Potential impact: this lays the foundation for simulating the transistors and circuits based on nanowire synaptic FETs. Nevertheless, further device physics study (possibly carried out with variable temperature measurement) is needed to determine the value of the constants used in the equations.
3. Developed the first simulation model to describe the spiking response of neuro-encoded electronic skin at the population level.
Potential impact: this lays the foundation for simulating the touch response of the neuro-encoded e-skin and is critical to further large-scale realisation and commercialisation.
Potential impact: this lays the foundation for realising large-scale electronics using printed nanowire ensembles. Nevertheless, extra optimisation in nanowire synthesis is needed to further improve the uniformity of the transistors.
2. Developed the mathematical equation sets to describe the synaptic behaviour from bottom-gated, nanowire transistor. This is the first proposed mathematical model of its kind.
Potential impact: this lays the foundation for simulating the transistors and circuits based on nanowire synaptic FETs. Nevertheless, further device physics study (possibly carried out with variable temperature measurement) is needed to determine the value of the constants used in the equations.
3. Developed the first simulation model to describe the spiking response of neuro-encoded electronic skin at the population level.
Potential impact: this lays the foundation for simulating the touch response of the neuro-encoded e-skin and is critical to further large-scale realisation and commercialisation.