ESR14 - Neural Nanowire Based Tactile Skin

Develop self-powered e-skin with neural nanowire field effect transistors based neural data processing hardware.

Overview

Objectives

Develop self-powered e-skin with neural nanowire field effect transistors based neural data processing hardware. Graphene is a proven nanomaterial for the fabrication of sensitive e-skin due to attributes such as flexibility, optical transparency and large area monolayer structure. Recent, a self-powered e-skin system combining a transparent graphene tactile sensor with a photovoltaic cell was shown to sufficient power (~20 nWcm−2) for the system to attain energy autonomy. Integration of such a tactile sensor with robotic and prosthetic limbs with smart data processing hardware is hugely beneficial. Additionally, we propose to use nanowires based neuromorphic circuits, that we demonstrated to be effective to carry out intricate tactile data processing. In this project, the ESR will develop graphene based e-skin and integrate it with υ-NWFET circuits. CVD graphene will be transferred over transparent PVC substrate using hot lamination technique and this will be followed by deposition of metal electrodes. Commercial PV cells will be integrated with the graphene sensor layer to obtain energy-efficient skin. Silicon NWs based floating gate FETs will be fabricated as a building block for neuromorphic data processing circuits.

Expected Results

A new strategy to process tactile information in robotic and prosthetic systems and the corresponding hardware neural network system based on Si nanowires.

Secondments

RUG

training on neuromorphic enigneering
IIT-iCub

e-skin comparison with POSFET devices with basic neural building blocks
SensArs

upcoming

Supervisors

R. Dahiya
E. Chicca
C. Bartolozzi
F. Petrini

Luca De Pamphilis

I first approached the study of nanotechnologies as I got fascinated by the quantum behaviour of nanostructures and their peculiar properties with respect to bulk materials. Growing more and more interested in the possible technological advancements allowed by the application of nanostructured materials and nanostructures, I focused my personal course of studies on nanotechnologies. Having learnt about the challenges that lie ahead for the research in this field, it is my desire to contribute to overcome them.

Neutouch for me

A stimulating, multidisciplinary project, Neutouch gives me the opportunity to put my background on nanotechnology into practice and face nanostructure integration challenges, co-working with researchers with different experiences and cultures, in a joint effort to tackle all the different aspects of an ambitious goal.

Info

Research Topics

Nanoengineering
Institution

University of Glasgow
Background

B.Sc. Materials Engineering and Nanotechnology (Politecnico di Milano, 2013-2017)
M.Sc. Materials Engineering and Nanotechnology (Politecnico di Milano, 2017-2020)

Thesis

Printed neuromorphic devices for electronic skin. University of Glasgow, 2024.

Abstract

Electronic skins (e-skins) are systems designed to provide robots and prosthetics with sensing capabilities similar to human skin’s. To replicate human skin’s high sensing acuity, e-skin must feature dense sensor arrays, continuously generating large datasets. This leads to high computational and energy costs in conventional computing architectures. An efficient alternative is offered by neuromorphic computing paradigms of localised, asynchronous, and parallel processing. The structural properties of e-skin require the neuromorphic circuits to be flexible and large-area. To satisfy these requirements, this thesis focuses on the development of the fundamental unit devices for neuromorphic e-skin flexible circuits via printed electronics-based fabrication processes.

As active electronic materials, ZnO nanowires (NWs) are selected for their versatile functionality (allowing both sensing and resistive switching), flexibility, and integrability over large area. To develop dense printed circuits, NW integration must also be site-selective. Hence, two suitable NW integration processes were developed: (i) selective NW removal, a lithography-free technique that allows high fidelity patterning of in-plane NW arrays, and (ii) selective hydrothermal synthesis, which allows the out-of-plane growth of NWs only in areas defined by the high-resolution electrohydrodynamic printing technique. These two complementary integration methods were employed for the fabrication of e-skin sensing and processing devices.

As sensing elements, flexible UV photodetectors are developed via a fully printed process, showing high performance (responsivity of 1.4×10⁷ A W⁻¹, record-high among ZnO-based photodetectors) with optimal performance retention upon bending. Then, digital memristors were fabricated via a roll-to-roll compatible process. These devices demonstrated high resistance switching (ON/OFF ratio ~10⁴) at ultralow biocompatible voltages (0.07 V SET, −0.06 V RESET) and robust performance under mechanical bending. Lastly, optoelectronic synapses are created by printing ZnO NWs over nanogap-separated electrodes. These devices demonstrated high bio-plausibility under both electrical and optical stimulation, exhibiting short-term synaptic plasticity functions, spike-rate-dependent plasticity, and transition from short- to long-term memory.

Publications

Luca De Pamphilis, Abhishek Singh Dahiya, Yuxin Xia, Evangelos Moutoulas, Dimitra G. Georgiadou, and Ravinder Dahiya, Coplanar Electrodes based Dual-Modulated Optoelectronic Memristive Synaptic Devices, NPJ Flex Electronics, 2025 (under review).

Luca De Pamphilis, Sihang Ma, Abhishek Singh Dahiya, Adamos Christou, and Ravinder Dahiya, Site-Selective Nanowire Synthesis and Fabrication of Printed Memristor Arrays with Ultralow Switching Voltages on Flexible Substrate, ACS Applied Materials & Interfaces 2024 16 (44), 60394-60403. DOI: 10.1021/acsami.4c07172

F. Liu, A. Christou, R. Chirila, L. De Pamphilis, R. Dahiya, Stochastic Nature of Large-Scale Contact Printed ZnO Nanowires Based Transistors. Adv. Funct. Mater. 2025, 35, 2412299. https://doi.org/10.1002/adfm.202412299

De Pamphilis, L., Dahiya, A. S., Christou, A., Ma, S., & Dahiya, R. (2022). Patterned assembly of inorganic semiconducting nanowires using lithography-free technique. IEEE Journal on Flexible Electronics, 2(2), 223-232.

Ma, S., Dahiya, A. S., Christou, A., De Pamphilis, L., & Dahiya, R. (2023). All-Printed ZnO Nanowire-Based High Performance Flexible Ultraviolet Photodetectors. IEEE Journal on Flexible Electronics, 2(2), 216-222.

De Pamphilis, L., Dahiya, A. S., Ma, S., & Dahiya, R. (2023, July). Printed Memristors Using Hydrothermally Grown Zinc Oxide Nanowires. In 2023 IEEE International Conference on Flexible and Printable Sensors and Systems (FLEPS) (pp. 1-4). IEEE.

De Pamphilis, L., Christou, A., Dahiya, A. S., & Dahiya, R. (2022, July). Selective removal of contact printed nanowires for lithography-free patterning. In 2022 IEEE International Conference on Flexible and Printable Sensors and Systems (FLEPS) (pp. 1-4). IEEE.

Neto, J., Dahiya, A. S., Christou, A., Zumeit, A., De Pamphilis, L., & Dahiya, R. (2023, July). Dual-Gate Transistors Using Contact Printed ZnO Nanowires. In 2023 IEEE International Conference on Flexible and Printable Sensors and Systems (FLEPS) (pp. 1-4). IEEE.

Luca De Pamphilis, Abhishek S. Dahiya, Ravinder Dahiya, ZnO Nanowire Based Flexible Transient Ultraviolet Photodetectors, Editor(s): A.S.M.A. Haseeb, Encyclopedia of Materials: Electronics, Academic Press, 2023, Pages 85-96, ISBN 9780128197356, https://doi.org/10.1016/B978-0-12-819728-8.00124-8.

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