The Department of Physics is delighted to welcome Dr Dimitra Georgiadou (University of Southampton) to give the tenth Physics Department Colloquium of Semester 2 2023/24. Please join us to listen to Dr Dimitra Georgiadou's seminar titled 'Nanoscale Materials and Devices for Greener Emerging Technologies'.
A reception will be held directly after the seminar, where tea and coffee will be provided.
The seminar is open to anyone from the university, students are encouraged to attend.
Title
Nanoscale Materials and Devices for Greener Emerging Technologies
Abstract
Nanotechnology is widely used in electronics to further miniaturise electronic components. Nanomaterials have played a major role in this, as they possess many attractive inherent properties derived from their low dimensionality. However, nanoparticles and self-assembled monolayers are usually processed from solution and they are difficult to be implemented with high yield in large area electronics. On the other hand, two-terminal electronic devices commonly comprise a generic metal/semiconductor/metal structure in a vertical (sandwich) configuration. This poses restrictions in the device fabrication when nanomaterials are involved, as the quality of the film is often compromised due to the small scale of the nanomaterials that do not guarantee uniform, continuous and pinhole-free film formation. A solution to this is offered by lateral devices, where the two metals are placed on the same plane and separated by a gap, which is filled by the semiconductor. If this gap is small enough, comparable to the dimensions of the materials used, the nanomaterials can effectively bridge this gap and connect the two electrodes electrically without causing a short-circuit.
Adhesion lithography (a-lith) is a nanopatterning technique with reduced manufacturing energy cost, as compared, for example, with e-beam lithography, that allows the fabrication of asymmetric nanogap metal electrodes at a low cost and with high throughput on a variety of rigid and flexible substrates of arbitrary size. We have so far demonstrated ultra-high speed (GHz) Schottky diodes (1) and fast photodetectors (2) as well as multi-bit and ferroelectric memories (3) based on different solution-processed semiconductors and a-lith patterned electrodes separated by a <10 nm gap.
In this talk I will present an overview of the work performed currently in my group at the University of Southampton, where we study different classes of materials, from metal oxides and polyoxometalates to organic materials and hybrid Pb-free perovskites, as well as layered 2D materials that are successfully implemented in nanoscale optoelectronic and memory applications. I will show that the combination of coplanar nanogap electrodes with functional materials holds great promise for achieving low power consumption and fast switching speeds in electronic devices, while their planar geometry facilitates a light-controlled operation, enabling optoelectronically controlled neuromorphic systems.
This work paves the way to the development of a new form of greener devices and systems that merge photonic, electronic and ionic effects, bringing new prospects for in-memory computing and artificial visual memory applications.
References
(1) Georgiadou, D.G., J. Semple, A.A. Sagade, H. Forstén, P. Rantakari, Y.-H. Lin, F. Alkhalil, A. Seitkhan, K. Loganathan, H. Faber, and T.D. Anthopoulos, 100 GHz zinc oxide Schottky diodes processed from solution on a wafer scale. Nature Electronics, 2020. 3(11): p. 718
(2) Georgiadou, D.G., Y.-H. Lin, J. Lim, S. Ratnasingham, M.A. McLachlan, H.J. Snaith, and T.D. Anthopoulos, High Responsivity and Response Speed Single-Layer Mixed-Cation Lead Mixed-Halide Perovskite Photodetectors Based on Nanogap Electrodes Manufactured on Large-Area Rigid and Flexible Substrates. Advanced Functional Materials, 2019. 0(0): p. 1901371
(3) Kumar, M., D.G. Georgiadou, A. Seitkhan, K. Loganathan, E. Yengel, H. Faber, D. Naphade, A. Basu, T.D. Anthopoulos, and K. Asadi, Colossal Tunneling Electroresistance in Co-Planar Polymer Ferroelectric Tunnel Junctions. Advanced Electronic Materials, 2020. 6(2): p. 1901091
Bio
Dr Dimitra Georgiadou is an Associate Professor and UKRI Future Leaders Fellow, leading the Flexible Nanoelectronics team in the School of Electronics and Computer Science at the University of Southampton, UK. She also serves as the Deputy Impact Champion and Recruitment Coordinator in the UKRI Centre for Doctoral Training (CDT) in Machine Intelligence for Nanoelectronic Devices and Systems (MINDS) and the Training Lead in UKRI CDT AI for Sustainability (sust.ai). Dimitra earned her PhD in Chemical Engineering/Organic Electronics from the National Technical University of Athens (NTUA), Greece. Before joining the University of Southampton, she was an Industrial Fellow at the Department of Materials and Marie Skłodowska-Curie Fellow at the Department of Physics of Imperial College London, UK. Her research interests are the fabrication and optimisation of nanoscale opto/electronic devices by applying novel materials concepts and alternative patterning techniques, which are compatible with flexible substrates. Her mission is to drive innovation in the field of materials science and engineering, with the ultimate goal of creating more efficient, sustainable, and intelligent systems to be applied in neuromorphic computing and the Internet of Things.