Invited Speaker：Prof. Alexander V. Kolobov

Report Title：Chalcogenide Nanoelectronics

Time: May. 9th, 2025, 10:00-12:00am

Location： Iharbour Gongxing Buliding 3-2014 Meeting Room (创新港校区 躬行楼（3号巨构）3-2014会议室)

Abstract: In this talk, after briefly discussing the exclusive role of chalcogenides in the history of semiconductors, I shall review three classes of chalcogenides, namely, (i) chalcogenide glasses, (ii) phase-change materials and (iii) two-dimensional chancogenides. The discovery by B.T. Kolomiets and N.A. Goryuniva of semiconducting properties of chalcogenide glasses (e.g. As2S3), despite the lack of long-range crystalline order in them, changed the then existing paradigm of the origin on band gap in semiconductors and opened up a new field of research - amorphous semiconductors. A characteristic feature of chalcogenide glasses is their ability to change reversibly their structure (and properties) under action of exter-nal stimuli such as light, making them important materials for photonic applica-tions. Chalcogenides received a new boost after the proposal by S.R. Ovshinsky to use the differences in structure between the crystalline and amorphous phase of some chalcogenides, mainly tellurides (GeTe, Sb2Te3 etc). These materials, called phase-change materials, are now widely used for optical memory devices and electronic von-volatile memory devices as well for reconfigurable photonics. Recently they are also investigated as promising materials for neuromorphic computing. The third class of materials covered in this talk are layered chalcogenides with van der Waals bonding between the layers. Examples include topological insulators (e.g. Sb2Te3), transition metal dichalcogenides (e.g. MoS2) and others (e.g. InSe). The use of these materials potentially allows one to build all-chalcogenide optoelecronic devices.

Introduction：A.V. Kolobov graduated in 1979 from the Leningrad Electrotechnical Institute and started his scientific career at the Ioffe Institute of the Academy of Sciences of the USSR. At various periods of time he worked at Cambridge University (UK), Ecole superieure de physique et de chimie industrielle de la ville de Paris (France), Leuven University (Belgium), CNRS (France), National Institute of Ad-vanced Industrial Science and Technology (Japan). From 2018 he is Head of De-partment of Physical Electronics and from 2021 - Director of the Institute of Physics at Herzen State Pedagogical University of Russia. He is recipient of the Kapitza Award of the Royal Society of London (1992) and Stanford Ovshinsky award for Excellence (2001). He published over 300 research papers, including those published in Nat. Mater, Nat. Chem. Nat. Nanotechnol., etc. Prof Kolobov is listed on the Stanford University list “Top 2% of the most cited scientists of the world”.