Abstract: An overview is presented for our recent study of graphene nanodevices for various challenging applications. Graphene nano-electro-mechanical (GNEM) device technology is first presented for low-power switching and ultra-sensitive chemical gas sensing applications. Three-terminal GNEM switches with heterogeneously stacked graphene / h-BN layers are developed, which achieve low-voltage and sub-thermal switching (S < 60 mV/dec). We then present nanoscale graphene chemical sensors, which detect either resistance or mass changes due to a small number of gas molecules physisorbed onto suspended graphene at room temperature. With the resistance detection method, we show quantized increments in the temporal resistance, signifying individual CO₂ molecule adsorption. As for the mass detection method, we demonstrate the resonance frequency shift of a doubly-clamped graphene resonator with the mass resolution of hundreds zeotpgram order. After that, state-of-the-art single-nanometer patterning technology of suspended graphene by using helium ion microscope (HIM) is introduced for nanoscale thermal engineering. The graphene nanomesh (GNM) structures with sub-10-nm pore diameter are patterned on large-area suspended graphene. A new Differential Thermal Leakage method is introduced to evaluate heat phonon transport in the asymmetric GNM channels. Remarkable thermal rectification is presented with the rectification ratio of over 80 % at 150 K and 60 % at 250 K along with preliminary discussion on physical mechanism behind the rectification phenomena.

Biography: Hiroshi Mizuta CPhys FInstP FJSAP, received the Ph.D. degree in electrical engineering from Osaka University, Japan, in 1993. He was the Laboratory Manager at the Hitachi Cambridge Laboratory, Cambridge, UK for 1997 – 2003. He was Associate Professor at Tokyo Institute of Technology for 2003 - 2007 and Professor of Nanoelectronics at University of Southampton for 2007 – 2016 (as part-time for 2011-2016) and served as Head of the NANO Group from 2009 - 2011. He is currently Distinguished Professor and Vice President (Special Missions) at Japan Advanced Institute of Science and Technology (JAIST) and Visiting Professor, School of Electronics and Computer Science, University of Southampton.

He has a strong track record in the research on silicon- and graphene-based nanoelectronic devices and nano-electro-mechanical-systems (NEMS). He has led a number of large research projects in the UK and Japan. He was awarded for 2018 Commendation for Science and Technology by the Ministry of Education, Culture, Sports, Science and Technology (MEXT), Japan for his research achievements on ‘Hybrid Electro-Mechanical Functional Devices at Nanoscale’. He has published over 620 peer-reviewed scientific papers and filed over 55 patents. He has also authored books and chapters, including “Physics and Applications of Resonant Tunnelling Diodes”, Cambridge University Press. Professor Mizuta is Fellow of the Japan Society of Applied Physics, Fellow of the Institute of Physics (IOP). For 2002-2016, he also served as a member of the International Advisory Board of the MacDiarmid Institute for Advanced Materials and Nanotechnology, New Zealand Centres of Research Excellences (CoREs).

Abstract: The speaker will use two examples of industrialized technology inventions to describe how to effectively combine and apply the two different disciplines of material chemistry and civil engineering, and talk about the stories of commercializing the research products. (1) Mixing cement with ice water to mass produce nanoparticles (size <5 nm), which could be used to prepare a series of hydrogels with super elasticity, adsorption and water swelling properties, applied in electronics, biological materials, agriculture, and civil engineering. (2) Low-cost, nanoparticle-stabilized foam that can keep stable for years, which could be used to mix with cement paste to prepare lightweight, high-strength, fire-resistant and thermally insulated foam concrete. The “nano-foam concrete” has been widely used in prefabricated building materials and cast-in-place construction projects.

Biography: Prof. Guoxing SUN received his Ph.D. degree in civil engineering from The Hongkong University of Science and Technology in 2015, and then worked for Nano and Advanced Materials Institute (NAMI), Hongkong. In 2017, he joined University of Macau, where he developed his career starting from assistant professor to associate professor, and was responsible for the industrialization of the new materials. He has conducted 20+ research grants of more than 4 million USD, and led a research group of more than 50 PhD students and Postdoctoral fellows, some of whom have been full professors in well-recognized universities.

Prof. Sun’s research focuses on polymer nanocomposites and construction materials. He discovered a simple way for mass producing 5 nanometer particles by just using normal cement and ice water, and designed a series of high-performance polymer nanocomposite hydrogels enhanced by these cement-released nanoparticles. In 2024, the research work was personally awarded the First-Class Prize in Technological Invention by Mr. Sam Hou Fai, Chief Executive of the Macao SAR.

Contributed to industrialization, Prof. Sun invented a nanoparticle-stabilized foam, which can be simply mixed with cement slurry to fabricate strong light-weight foam concrete. The nano-foam concrete can be 2-5 times stronger or 40% lighter than the relevant market products. It has been widely used and saved 15-40% of cement usage in various construction projects of 15 cities all around the world, such as the largest land port of China, Zhuhai-Macao Hengqin Port Comprehensive Transportation Hub, and Macau Cross-Sea Bridge.

Prof. Sun was reported by China Central Television (CCTV-1, CCTV-4 and CCTV-13) for several times. He is also the recipient of the China National Excellent Young Scientists Fund (2021), Macau Science and Technology Award (2024 and 2022), Building Science and Technology Award issued by China Building Materials Federation (2018). He published over 150 papers in referred journals with total cited times over 7000, and was recognized as World’s Top 2% Scientists in the past two years.