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(2020) Mark Hersam: Atomically Thin Neuromorphic Computing Materials and Devices

posted 15 Feb 2021, 11:55 by Peter Boggild

Department of Materials Science and Engineering, Northwestern University, USA
2220 Campus Drive, Evanston, IL 60208-3108, USA 
m-hersam@northwestern.edu; http://www.hersam-group.northwestern.edu/

The exponentially improving performance of conventional digital computers has slowed in recent years due to the speed and power consumption issues that are largely attributable to the von Neumann bottleneck (i.e., the need to transfer data between spatially separate processor and memory blocks). In contrast, neuromorphic (i.e., brain-like) computing aims to circumvent the limitations of von Neumann architectures by spatially co-locating processor and memory blocks or even combining logic and data storage functions within the same device. In addition to reducing power consumption in conventional computing, neuromorphic devices also provide efficient architectures for emerging applications such as image recognition, machine learning, and artificial intelligence [1]. With this motivation in mind, this talk will explore the opportunities for atomically thin materials in neuromorphic devices. For example, by combining p-type single-walled carbon nanotube thin films with n-type transition metal dichalcogenides, gate-tunable diodes have been realized, which show anti-ambipolar transfer characteristics that are suitable for artificial neurons, competitive learning, and spiking circuits [2]. In addition, by exploiting field-driven defect motion mediated by grain boundaries in monolayer MoS2, gate-tunable memristive phenomena have been achieved, which enable hybrid memristor/transistor devices (i.e., “memtransistors”) that concurrently provide logic and data storage functions [3]. The planar geometry of memtransistors further allows multiple contacts to the channel region that mimic the behavior of biological neurons such as heterosynaptic responses [4]. Overall, this work introduces new foundational circuit elements for neuromorphic computing in addition to providing alternative pathways for studying and utilizing the unique charge transport characteristics of atomically thin materials and heterostructures [5].

[1] V. K. Sangwan, et al., Nature Nanotechnology, DOI: 10.1038/s41565-020-0647-z (2020).
[2] M. E. Beck, et al., Nature Communications, 11, 1565 (2020).
[3] V. K. Sangwan, et al., Nature Nanotechnology, 10, 403 (2015).
[4] V. K. Sangwan, et al., Nature, 554, 500 (2018).
[5] D. Jariwala, et al., Nature Materials, 16, 170 (2017).

Mark C. Hersam is the Walter P. Murphy Professor of Materials Science and Engineering and Director of the Materials Research Center at Northwestern University. He also holds faculty appointments in the Departments of Chemistry, Applied Physics, Medicine, and Electrical Engineering. He earned a B.S. in Electrical Engineering from the University of Illinois at Urbana-Champaign (UIUC) in 1996, M.Phil. in Physics from the University of Cambridge (UK) in 1997, and a Ph.D. in Electrical Engineering from UIUC in 2000. His research interests include nanomaterials, nanomanufacturing, scanning probe microscopy, nanoelectronic devices, and renewable energy. Dr. Hersam has received several honors including the Presidential Early Career Award for Scientists and Engineers, TMS Robert Lansing Hardy Award, AVS Peter Mark Award, MRS Outstanding Young Investigator, U.S. Science Envoy, MacArthur Fellowship, and eight Teacher of the Year Awards. An elected member of the National Academy of Inventors, Dr. Hersam has founded two companies, NanoIntegris and Volexion, which are commercial suppliers of nanoelectronic and battery materials, respectively. Dr. Hersam is a Fellow of MRS, AVS, APS, AAAS, SPIE, and IEEE, and also serves as an Associate Editor of ACS Nano.

Mark Hersam