Centre for Disruptive Photonic Technologies
School of Physical and Mathematical Sciences Nanyang Technological University, Singapore

Dr. Ze Xiang Shen is a Professor in the School of Physical and Mathematical Sciences, and the School of Materials Science and Engineering, Nanyang Technological University. He is the Program Chair of the Interdisciplinary Graduate School. He concurrently holds the position of Co-Director, Centre for Disruptive Photonics Technologies.

His main research areas include carbon related materials, especially graphene.  His work involves spectroscopic and theoretical study of few-lay graphene and folded graphene, graphene intercalation study, graphene based composites for energy harvesting (Li Ion batteries and supercapacitors) and nano electronics; fundamental study of graphene such as electronic structures, doping, energy band gaps. He also works on developing near-field Raman spectroscopy/imaging techniques and the study of plasmonics structures where some very fundamental questions remain to be answered.
He was awarded the NTU Nanyang Award for Research and Innovation 2009 as well as the Gold Medal for Research Excellence by Institute of Physics Singapore in 2011. Shen authored over 400 peer reviewed journal papers, 4 book chapters, edited 3 books and over 300 conference papers.  He has a citation of >10,000 and H-index of 58.

Understanding graphene: from fundamental study to edge modification, intercalation and applications

In this talk, I will present our results of graphene study: understanding on graphene intercalation, and properties of folded and mis-oriented graphenes. With the availability of few-layer graphene, we shed new light on the mechanism of intercalation of graphite which is not possible before [1,2]. Folded graphene sheets exhibit two-dimensional Dirac-like (single layer graphene-like) character of electronic states and with reduction of Fermi velocity [3]. For applications in nano-electronic devices and energy harvesting, opening of the band gap is needed. On the other hand, many of the unique properties of graphene are accorded to that of single layer graphene (SLG). But it is very difficult to fabricate large single crystalline SLG samples for practical applications. It would be most desirable to modify few-layer graphene (FLG) samples so that they have similar properties as that of SLG. I will also present our results in modifying graphene for various applications, including applications in energy storage.

[1] D. Zhan, L. Sun, Z. H. Ni, L. Liu, X. F. Fan, Y. Y. Wang, T. Yu, Y. M. Lam, W. Huang, Z. X. Shen, FeCl3-Based Few-Layer Graphene Intercalation Compounds: Single Linear Dispersion Electronic Band Structure and Strong Charge Transfer Doping, 20 (2010) Advanced Functional Materials 3504.
[2] ZH Ni, HM Wang, J Kasim, HM Fan, T Yu, YH Wu, YP Feng, ZX Shen, Graphene thickness determination using reflection and contrast spectroscopy, Nano Letters 7 (2007) 2758.
[3] ZH Ni, YY Wang, T Yu, YM You, ZX Shen, Reduction of Fermi velocity in folded graphene observed by resonance Raman spectroscopy. 77(2008), Physical Review B 235403
[4] D Zhan, L Liu,YN Xu, ZH Ni, JX Yan, C Zhao, ZX Shen, Low temperature edge dynamics of AB-stacked bilayer graphene: Naturally favored closed zigzag edges, Scientific Report, 1 (2011)12.
[5] Wenjing Zhang, Jiaxu Yan, Chang-Hsiao Chen, Liu Lei, Jer-Lai Kuo, Zexiang Shen & Lain-Jong Li, Molecular adsorption induces the transformation of rhombohedral- to Bernal-stacking order in trilayer graphene, Nature Communications, 4:2074 (2013)