Lanza Research Group

On December 17^th-18^th_, our group participated in the 2nd International Workshop on Future Computing (Shenzhen). This conference attracted many famous researchers worldwide in neuroscience, neuromorphic architecture and memristive field. We also posted three of our recent works on resistive switching and during the poster session, everyone learnt a lot by sharing their own experience and exchanging opinions.

Image: Shaochuan Chen, Chao Wen, Xu Jing, Mario Lanza, Kaichen Zhu, Fei Hui, Tao Wang (from left to right)

Yuanyuan Shi receives the prestigious EDS excellent PhD student award. The prize was given in a solemn ceremony at the 2018 International Electron Devices Meeting, held in San Francisco (USA) between December 1st and 5th, 2018.

Image: Fernando Guarin, Yuanyuan Shi and Junkai Jiang (from left to right)

Starting from 2001, three winners are selected worldwide to receive the award each year to promote, recognize and support PhD level study and research within the EDS field.  Yuanyuan Shi shared the stage with Fernando Guarin (president of EDS and Junkai Jiang (another winner). Congratulations, Yuanyuan !

Professor Mario Lanza has been recently appointed as member of the Editorial Board of Advanced Electronic Materials, a multidisciplinary journal from Nature Publishing Group with an impact factor of 5.466.  Prof. Lanza has joined the “Electronics, Photonics and Device Physics Panel”, and he will be in charge of: i) assessing whether manuscripts should be sent for peer review, ii) managing the peer review of manuscripts and make final editorial decisions – whether to accept, reject or allow resubmission, and iii) act as an advocate for Advanced Electronic Materials. This is an important achievementand, together with his previous appointment at the board of Crystal Research & Technology (Wiley-VCH), indicates the high influence of Prof. Lanza in the field of electronics and applied physics. Congratulations !!!

On February 12^th of 2019, Prof. Mario Lanza, full Professor at the Institute of Functional Nano & Soft Materials of Soochow University, has been selected as Distinguished Lecturer by the Electron Devices Society (EDS) of the USA, which belongs to the prestigious Institute of Electrical and Electronic Engineers (IEEE). Prof. Lanza received this distinction for extraordinary contributions in the field of “Two-dimensional materials based electronic devices”. The high selectivity of this distinction can be seen by the fact that in Mainland China there are only four scientists who received it, and the other three are: Prof. Ru Huang (Peking University, Academician), Prof. Ming Liu (Chinese Academy of Sciences, Academician), and Prof. Tian-Lin Ren (Tsinghua University, Chang Jiang Scholar). Congratulations to Prof. Mario Lanza for this achievement!

Complete list of Distinguished Lecturers of the Electron Devices Society:

https://eds.ieee.org/lectures/distinguished-lecturer-listing.html

The research group led by the Prof. Mario Lanza, based at the Institute of Functional Nano & Soft Materials of Soochow University, has developed memristors capable of partially emulating the behavior of biological synapses in the human brain. Synapses are nerve endings that connect neurons in the brain, and have the function of transmitting (or not) the electrical impulses that these generate. To do this, the synapses change their resistivity by secreting calcium and sodium ions. In a very similar way, memristors are two terminals electronic devices nano-structured in the form of conductor/insulator/conductor, in which the insulating layer can change its resistivity depending on the electrical impulses applied to the input by secreting ions of oxygen or metal.

Despites memristors were considered the most promising electronic device to emulate the behavior of biological synapses, until now their main limitation was that memristors made of traditional materials (metals and oxides) had many difficulties in emulating the dynamic behavior of a synapse. In other words, the changes in resistivity in a traditional memristor were produced very abruptly between two states depending on the applied electrical impulses, while in a synapse the modulation of the resistivity is more progressive and its relaxation depends much more on the time. The memristors developed by the group of Prof. Mario Lanza show, for the first time, a very progressive, stable and repetitive relaxation process, which represents a new world record. In addition, these memristors allow to work in volatile or non-volatile mode depending on the electrical impulses applied to the input, as biological synapses do. These advances have been possible thanks to the introduction of two-dimensional materials in the structure of the memristors, such as multi-layer hexagonal boron nitride (also called white graphene). These results, published this week in Nature Electronics, represent a major breakthrough for the manufacture of artificial neural networks, which are computational structures essential for the development of advanced artificial intelligence systems.

Image : Conductive filament formed in a metal/h-BN/metal electronic synapse after applying an electrical stress between the electrodes. Silver, blue and yellow spheres represent metal, nitrogen and boron atoms.

In the morning of July 6^th, Dr. Umberto Celano (Senior Researcher, IMEC) visited our group and gave an invited talk titled “Scalpel SPM toward the three-dimensional characterization of confined volumes”. In this talk, he shared his latest work on the use of novel scanning probe microscopy (SPM) tomography to characterize different types of materials and devices. Afterward, we had a lab tour and introduced the development of our institute and group. Dr. Celano is the recipient of the Nano Letters Young Investigator Award and published his PhD thesis as a book in Springer.

Image: Kaichen Zhu, Dr. Umberto Celano, Fei Hui (from left to right) by the Jinji Lake

On July 4^th – 7^th, our group members Shaochuan Chen, Bin Yuan, Xianhu Liang and Mario Lanza participated in the 24^th IEEE International Symposium on the Physical and Failure Analysis of Integrated Circuits (IPFA) in Chengdu, China. In the conference, Prof. Mario Lanza was invited to give a tutorial talk on “Conductive atomic force microscopy and its use in nanoelectronic device reliability” and an invited talk on “TiO₂/SiO_x bilayer insulating stacks for filamentary/distributed resistive switching”. It’s a great experience to take part in the conference and we got the opportunity to interact with the top experts in the field.

Image:  Prof. Mario Lanza (right) with Conference chairs

The use of two dimensional (2D) materials to improve the capabilities of electronic devices is a promising strategy that has recently gained much interest in both academe and industry. In this paper, we develop resistive random access memories (RRAM) using 2D material. We use for the first time layered h-BN as resistive switching medium, and engineered a new family of devices with different perforances. This invention has been protected with an international patent, and the results have been published in Advanced Functional Materials, which has an impact factor of 11.38. This investigation has been developed in collaboration with the Massachusetts Institute of Technology, Stanford University and Harvard University. This breaking report represents an important milestone towards the implementation of advanced digital electronic devices using 2D materials.

Schematic, cross-sectional TEM image and typical behavior of the Ti/h-BN/Cu RRAM devices developed in our group.

Fei started to work in this project in September of 2013. She has developed a cost-effective and scalable approach to fabricate graphene-coated nanoprobes. Her work was published in Nanoscale and Surface & Coatings Technology, and protected with an international patent. Now, we received generour investment of near 1 million USD fromt the Beijing Institute of Collaborative Innovation to introduce this product in the market.

(Left) Standard metal-varnished nanoprobe for CAFM. (Right) Standard metal-varnished nanoprobe for CAFM coated with a thin film of single layer graphene. (Center) Schematic of the graphene coated nanoprobe.