B.Sc., Nanjing Univ., 2001; Ph.D., National University of Singapore., 2004;Postdoc, National University of Singapore, 2004-2006; Lee Kuan Yew Research Fellow, National University of Singapore, 2006-2008
Department of Chemistry, NUS
We are interested in molecule-substrate interface problems associated with molecular electronics, organic electronics and graphene-related devices, including:
1. Self-assembled functional molecular nanostructure arrays for their applications in molecular electronics, organic electronics, and solid state quantum computation
Molecular self-assembly on surfaces or surface nanotemplates via weak but selective noncovalent interactions, including electrostatic forces, hydrogen bonds, van-der-Waals forces, and metal-ligand interactions, offers a promising bottom-up approach to fabricate molecular nanostructure arrays with desired functionalities over macroscopic areas. The objectives of this sub-program are (i) to understand how the intermolecular interactions and molecule-substrate interfacial interactions determine the molecular self-assembly on surfaces, and (ii) to fabricate tunable and well-ordered 2D arrays of molecular nanostructures for device applications. The experiments will be carried out in a customer-designed low-temperature scanning tunneling microscopy (LT-STM, Omicron).
2. Molecular-level interface controlled organic thin films for organic photovoltaic devices
The aim of this sub-program is to investigate the interface properties of various molecular-level interface-controlled organic thin films or organic-organic heterojunctions, including electronic energy level alignment at the molecule-substrate interfaces, supramolecular packing and molecular orientation at the organic-organic heterojunctions, orientation dependent interface properties, and the charge and energy transfer at the organic-organic heterojunction interfaces. The experiments will be mainly carried out in a Singapore synchrotron light source (SSLS) using high-resolution photoemission spectroscopy (PES), near-edge x-ray absorption fine structure measurement (NEXAFS) and resonant photoemission spectroscopy (RPES).
3. Interface problems associated with graphene-related devices
Monocrystalline graphitic films with one or few-layer thickness have attracted much attention recently due to their exotic properties, such as the existence of massless Dirac fermions, quantum Hall effect, and gate control of transport (electron or hole) properties. In particular, it has been demonstrated that ultrathin graphene films epitaxially grown on commercial silicon carbide substrates by thermal decomposition in vacuum can be patterned using standard nanolithography methods, making it compatible with current semiconductor technology. The main aim of this project targets for the large scale (wafer-size) production of high-quality graphene films for their device application. The growth mechanism, surface transfer doping, electronics structures of graphene, and various surface modification schemes to manipulate the electronic properties of graphene will be also studied.
“Electrical Measurement of Non-destructively p-type Doped Graphene using Molybdenum Trioxide” Xie LF, Wang X, Mao HY, Wang R, Ding MZ, Wang Y, Özyilmaz B, Loh KP, Wee ATS, Ariando*, Chen Wei* Appl. Phys. Lett. 99, 012112 (2011).
“Room Temperature Ferromagnetism in Partially Hydrogenated Epitaxial Graphene” Xie LF, Wang X, Lu J, Luo ZQ, Mao HY, Wang R, Wang YY, Huang H, Qi DC, Liu R, Yu T, Shen ZX, Wu T, Peng HY, Özyilmaz B, Loh KP, Wee ATS, Ariando*, Chen Wei* Appl. Phys. Lett. 98, 193113 (2011).
“Mechanism of the Fermi Level Pinning at Organic Donor-Acceptor Heterojunction Interfaces” Mao HY, Bussolotti F, Qi DC, Wang R, Kera S, Ueno N, Wee ATS, Chen Wei* Organic Electronics 12, 534-540 (2011).
“Molecular trapping on Two-dimensional Binay Supramolecular Networks” Huang YL, Chen Wei*, Wee ATS*, J. Am. Chem. Soc. 133, 820–825 (2011).
“Organic-Organic Heterojunction Interfaces: Effect of Molecular Orientation” (invited review article)
Chen Wei*, Qi DC, Huang H, Gao XY, and Wee ATS*, Advanced Functional Materials 21, 410-424 (2011)
“One Dimensional Molecular Dipole Chain Arrays on Graphite via Nanoscale Phase Separation” Huang YL, Wang R, Niu TC, Kera S, Ueno N, Pflaum J, Wee ATS, Chen Wei*, Chemical Communication46,9040–9042 (2010).
“Tuning of C60 Energy Levels Using Orientation-Controlled Phthalocyanine Films” Ma HY, Wang R, Huang H, Wang YZ, Gao XY, Bao SN, Wee ATS, Chen Wei* J. Appl. Phys. 108, 053706 (2010).
" Surface Transfer Hole Doping of Epitaxial Graphene using MoO3 Thin Film" Chen ZY, Santoso I, Wang R, Xie LF, Mao HY, Huang H, Wang YZ, Gao XY, Chen ZK, Ma DG, Wee ATS, Chen Wei*, Appl. Phys. Lett. 96, 213104 (2010).
"Atomic Scale Oxidation of Silicon Nanoclusters on Silicon Carbide Surfaces". Chen Wei, Xie XN, Xu H, Wee ATS, Loh KP*, J. Phys. Chem. B. 107, 11597 (2003).
1. Chen Wei, Chen ZY, Wee ATS, "Hole Doping Methods for Graphene", US 61/343,886, 2010.
2. Chen Wei, Xie Lan Fei, Wang Xiao, Sun Jia Tao, Ariando, Wee ATS"Fabrication of Room-Temperature Ferromagnetic Graphene by Surface Modification with High Work Function Metal Oxides" US, 61/404,975, Oct 2010
Publications on peer-reviewed journals (* for corresponding authors)
Total citations > 1200 H-index: 22
6. "LT-STM Studies of Substrate-Dependent Self-Assembly of Small Organic Molecules"
(invited review article) Huang H*, Wong SL, Chen Wei, and Wee ATS*, J. Phys: D. Appl. Phys. (submitted).
5. "Organic-Organic Heterojunction Interfaces: Effect of Molecular Orientation" (invited review article)
Chen Wei*, Qi DC, Huang H, Gao XY, and Wee ATS*, Advanced Functional Materials 21, 410-424 (2011).
4. "Surface Transfer Doping of Semiconductors" (invited review article)Chen Wei*, Qi DC, Gao XY, and Wee ATS*, Prog. Surf. Sci. 84, 279-321 (2009).
3. "Synchrotron PES, RPES and NEXAFS studies of self-assembled aromatic thiol monolayers on Au(111)" (invited review article) Chen Wei, and Wee ATS*, J. Electron Spectrosc. Relat.Phenom. 172, 59-63 (2009).
2. "Charge Transfer across the Molecule/Metal Interface using the Core Hole Clock Technique" (invited review article) Wang L, Chen Wei, and Wee ATS*, Surf. Sci. Rep. 63, 465-486 (2008).
1. "Self-assembly on silicon carbide nanomesh templates" (invited review article) ChenWei, and Wee ATS*, J. Phys: D. Appl. Phys. 40, 6287 (2007).
1. "STM Studies of Molecule-Metal Interfaces" (invited book chapter) Wong SL, Huang H, Wee ATS and Chen Wei*,, in "The Molecule-Metal Interface", edited by Norbert Koch, Nobuo Ueno and Andrew T. S. Wee, Wiley
2. "NEXAFS Studies of Molecule-Metal Interfaces" (invited book chapter) Qi DC*, Chen Wei,* Wee ATS, in "The Molecule-Metal Interface", edited by Norbert Koch, Nobuo Ueno and Andrew T. S. Wee, Wiley
3. "In-situ STM studies of molecular self assembly on surfaces" (invited book chapter)Chen Wei*, and Wee ATS*, in "Scanning Probe Microscopy: techniques, applications and future directions", p37-55, edited by Nikodem Tomczak and Kuan Eng Johnson Goh, World Scientific, Singapore.
Papers selected as journal cover or Frontispiece Paper:
4. "Tunable two-dimensional binary molecular networks" Huang YL, Chen Wei*,
Li H, Pflaum J, Ma J, Wee ATS*, Small 6, 70-75 (2010). Selected as Frontispiece Paper.
3. "Low- Temperature Scanning Tunneling Microscopy Investigation of
Epitaxial Growth of F16CuPc Thin Films on Ag(111)" Huang H, Chen Wei*, Wee ATS*, J. Phys. Chem. C. 112, 14913-14918 (2008). Cover in issue 39 25th Sep.
2. "Self-Assembled Organic Donor/Acceptor Nanojunction Arrays" Chen Wei*, Zhang HL, Huang H, Chen L, Wee ATS*, Appl. Phys. Lett. 92, 193301 (2008) (cover image in the 12th May issue). Highlighted by Nature
Nanotechnology 3, 375 (2008).
1. "Atomic force microscopy study of hexagonal boron nitride film growth on 6H-SiC (0001)", Chen Wei, Loh KP*, Lin M, Liu R, and Wee ATS, Phys. Stat. Sol. (a), 202 , 37 (2005). Front cover and editor's choice.