Tong Leung

Professor, Chemistry

Research interests: chemical physics; surface chemistry; nano-materials; nano-devices; nano-biotechnology

Biography

Professor Tong Leung and his research group are investigating coreshell metal nanoparticles (Cr, Mn, Ni,Fe, Co, Ni, Cu) and metal-oxide (CrO₂, ZnO, TiO₂) nanostructured materials. These nanostructures range from 7 to 200 nanometres in size, and exhibit a variety of novel structures and morphologies, including nanoneedles, nanowalls, nanodisks, nanospikes, nanopillars, nanowires and nanotubes.

New fabrication methods of nanostructures are being developed on a conducting polymer (polypyrrole) substrate, single-crystal silicon, and on Indium-Tin-Oxide coated glass or plastic by both (wet) electrochemical deposition and (dry) pulsed laser deposition techniques. The research group seeks to develop a better understanding of the growth mechanism and structure-properties relationships, and the surface physics and chemistry. These studies also focus on several strategic applications, zinc oxide nanostructures on ITO including; CrO₂ based spin-valve for spintronics; metal and metal-oxide based nanocatalysi; two-dimensional nanostructured ZnO field-emitters for the nextgeneration display technology; and quantum-dot photovoltaics.

Using electron beam lithography and nanolithography, Leung’s group designs and builds simple nanodevices, with the specific goal to investigate the substrate effects of different nanoscale geometric patterns on the growth physics and surface and electronic properties of the deposited nanostructures. Current projects also attempt to develop flexible display involving ZnO nanowalls on plastic-ITO, spin-based electronic components based on CrO₂ nanoneedles/micropallets, and grid-based hybrid biosensors.

In the area of bio-nanotechnology, the focus is on biomolecular electronics and macromolecular nanodevices. Using a state-of-the-art molecular beam epitaxy instrument, the surface chemistry of DNA-based biomaterials is probed as functions of surface concentration, substrate temperature, nanocluster size and morphology. The chemical physics and surface chemistry of these biomolecular nanomolecules, particularly their electron transfer and temperature evolution behaviours, are investigated by using scanning probe and other surface science techniques. Using the MAPLE and Langmuir-Brodgett deposition bio-tools, Leung’s group is also studying the self-assembly of ferritin and cholesterol to develop applications in bioorganic data storage and chemical sensors.

Education

PhD, Chemistry, University of British Columbia, 1984
BSc, Physics and Chemistry, University of British Columbia, 1980

Tong Leung

Research

Research Interests

Chemical physics and surface chemistry
Semiconductor surface science and molecular electronics
Spectromicroscopy and nano-metrology
Nanofabrication, lithography and patterning (CD, PLD, MBE)
Spintronics, magnetic nanomaterials, bio-nanomaterials.

Research facilities

As one of Canada’s premier materials research laboratories, theWaterloo Advanced Technology Laboratory (WATLab) is equipped with a full range of state-of-the-art instrument-clusters for:

Microscopy

Ultrahigh-vacuum-based scanning probe microscope (Omicron VT-SPM), atomic force microscope (DI Nanoscope IV), scanning electron microscope (Zeiss FESEM 1530), 4-circle high-resolution X-ray diffractometer (PANalytical Xpert Pro MRD);

Spectromicroscopy

Imaging ESCA microprobe (Thermo VG ESCALab 250), scanning auger microscope (Thermo VG MicroLab 350), raman confocal microscope (Bruker Senterra), UV/Vis, photoluminescence and FTIR spectrometers;

Nanofabrication

Electrochemical workstations and microbalance, pulsed laser deposition (PVD NanoPLD and MAPLE), molecular beam epitaxy (Omicron); and
lithography and patterning: electron-beam lithography (Raith-Navidy), nanolithography (DI Nanoman).

WATLab not only offers a unique interactive environment for multidisciplinary advanced research and training to university researchers that is second to none in Canada, but also provides important research and development services to local industries in Canada’s Technology Triangle (Kitchener-Waterloo, Cambridge, and Guelph).

Publications

Recent publications include:

N. Moghimi, M. Abdellah, J.P. Thomas, M. Mohapatra, K.T. Leung, J. Am. Chem. Soc. (Comm.) 135 (2013) 10958-61. “Bimetallic FeNi concave nanocubes and nanocages”
A. Chatterjee, L. Zhang, K.T. Leung, Langmuir 29(2013) 9369-9377. "Self-directed growth of aligned adenine molecular chains on Si(111)7x7: direct imaging of hydrogen-bond mediated dimers and clusters at room temperature by scanning tunneling microscopy"
A. Chatterjee, L. Zhang, K. T. Leung, J. Phys. Chem. C 117 (2013) 14677-83. “Surface [4+2] cycloaddition reaction of Thymine on Si(111)7×7 observed by Scanning Tunnelling Microscopy”
J.P. Thomas, L. Zhao, M. Abd-Ellah, N.F. Heinig, K.T. Leung, Anal. Chem. 85 (2013) 6840-5. “Interfacial micropore defect formation in PEDOT:PSS-Si hybrid solar cells probed by TOF-SIMS 3D chemical imaging”
S. Bazargan, K.T. Leung, J. Appl. Phys. 113 (2013) 234305 (6 pp). “Magnetic interaction and conical self-reorganization of aligned Tin Oxide nanowire array under field emission conditions”
N. Moghimi, K.T. Leung, Anal. Chem. 85 (2013) 5974-80. “FePt alloy nanoparticles for bio-sensing: Enhancement of Vitamin C sensor performance and selectivity by nanoalloying”
L. Zhao, K. Liao, M. Pynenburg, L. Wong, N. Heinig, J.P. Thomas, K.T. Leung, ACS Applied Materials & Interfaces 5(2013) 2410-2416. "Electro-oxidation of ascorbic acid by cobalt core-shell nanoparticles on a H-terminated Si(100) and by nanostructured cobalt-coated Si nanowire electrodes"
M. Abd-Ellah, N. Moghimi, L. Zhang, N.F. Heinig, L. Zhao, J.P. Thomas, K.T. Leung, Journal of Physical Chemistry C 117 (2013) 6794-6799. "Effect of electrolyte conductivity on controlled electrochemical synthesis of zinc oxide nanotubes and nanorods"
S. Bazargan, K.T. Leung, Journal of Chemical Physics, 138 (2013). "Growth of randomly oriented single-crystalline tin (IV) oxide nanobelts: control on the predominant crystalline growth axis"
N. Moghimi, S. Bazargan, D. Pradhan, K.T. Leung, Journal of Phyiscal Chemistry C 117 (2013) 4852-4858. "Phase-induced shape evolution of FeNi nanoalloys and their air stability by in-situ surface passivation"
L. Zhao, N. Heinig, K.T. Leung, Langmuir 29 (2013) 927-931. "Formation of Au-Pt Alloy Nanoparticles on a Si Substrate by Simple Dip-Coating at Room Temperature"
Chatterjee, L. Zhang, K. T. Leung, J. Phys. Chem. C 116 (2012) 10968-75. “Direct imaging of hydrogen bonding formation in dissociative adsorption of glycine on Si(111)7×7 by Scanning Tunneling Microscopy”
S. Bazargan, K.T. Leung, J. Phys. Chem. C 116 (2012) 5427-34. “Catalyst-assisted Pulsed Laser Deposition of one-dimensional single-crystalline nanostructures of Tin (IV) Oxide: Interplay of VS and VLS growth mechanisms at low temperature”
Y.K. Sohn, D. Pradhan, L.Y. Zhao, K.T. Leung, Electrochemical and Solid-Sate Letters 15 (2012) K35-39. “Anomalous oxidation resistance of “core-only” copper nanoparticles electrochemically grown on gold nanoislands prefunctionalized by 1,4-phenylene diisocyanide”
S. Bazargan, N.F. Heinig, J.F. Rios, K.T. Leung, J. Phys. Chem. C 116 (2012) 4979-85. “Electronic Transport in Tin(IV) Oxide Nanocrystalline Films: Two-Medium Transport with Three-Dimensional Variable-Range Hopping Mechanism for the Ultrasmall Nanocrystallite Size Regime.” [Cover-page]
D. Pradhan, Z. Su, S. Sindhwani, J.F. Honek, K.T. Leung, J. Phys. Chem. C 115 (2011) 18149-56. “Electrochemical growth of ZnO nanobelt-like structures at 0^oC: Synthesis, characterization, and in-situ glucose oxidase embedment."
L. Zhang, A. Chatterjee, K.T. Leung, J. Phys. Chem. C 115 (2011) 14155-63. “Three-stage growth of glycine and glycylglycine nanofilms on Si(111)7x7 and their thermal evolution in ultrahigh vacuum conditions: From chemisorbed adstructures to transitional layer to zwitterionic films."
Radi, K.T. Leung, Mater. Exp. 1 (2011) 144-53. “Competitive bondng of amino and hydroxyl groups in ethanolamine on Si(100)2x1: Temperature-dependent X-ray photoemission and thermal desorption studies of nanochemistry of a double-chelating agent."
Chatterjee, L. Zhang, K.T. Leung, Chem. Phys. Lett. 508 (2011) 219-23. “Computational surface chemistry of glycine on Si(111)7x7 and Si(100)2x1: Dissociative adsorption through adduct formation."
D. Pradhan, S.K. Mohapatra, S. Tymen, M. Misra, K.T. Leung, Mater. Exp. 1 (2011) 59-67. “Morphology-controlled ZnO nanomaterials for enhanced photoelectrochemical performance."
S. Jamali Gharetape, M.P. Singh, F.S. Razavi, D.A. Crandles, L.Y. Zhao, K.T. Leung, Appl. Phys. Lett. 98 (2011) 052509. “Effect of vanadium deficiency on properties of polycrystalline LaVO₃"
S. Bazargan,N.F. Heinig, D. Pradhan, K.T. Leung, Crystal Growth & Design 11 (2011) 247-55. “Controlled growth of monodisperse nanocrystallites in tin(IV) oxide nanofilms."
L. Zhang, A. Chatterjee, K.T. Leung, J. Phys. Chem. Letters. 1 (2010) 3385-90. “Hydrogen-bond medidated biomolecular trap: Reversible catch-and-release process of common biomolecules on a glycine-Si(111)7x7 template."
D. Pradhan, S. Sindhwani, K.T. Leung, Nanoscale Res. Lett. 5 (2010) 1727-36. “Parametric study on dimensional control of ZnO nanowalls and nanowires by electrochemical deposition.”
Y.K. Sohn, D. Pradhan, K.T. Leung, ACS Nano 4 (2010) 5111-20. “Electrochemical Pd nanodeposits on a Au nanoisland template supported on Si(100): Formation of Pd-Au alloy and interfacial electronic structures”
D. Pradhan, F. Niroui, K.T. Leung, ACS Appl. Mat. Int. 2 (2010) 2409-12. “A high-performance, flexible enzymatic glucose biosensor based on ZnO nanowires supported on a gold-coated polyester substrate.”
H. Jalili, N.F. Heinig, K.T. Leung, J. Chem. Phys. 132 (2010) 204701. “Growth evolution of laser-ablated Sr2FeMoO6 nanostructured films: Effects of substrate-induced strain on the surface morphology and film quality.”
V. Venugopal, A. Chatterjee, M. Ebrahimi, K.T. Leung, J. Chem. Phys. 132 (2010) 174702. “Adsorption and thermal decomposition of acetic acid on Si(111)7×7 studied by vibrational electron energy loss spectroscopy”
Radi, M. Ebrahimi, K.T. Leung, Surf. Sci. 604 (2010) 1073-81. “Relative reactivities of amino and ethenyl groups in allylamine on Si(100)2×1: Temperature-dependent X-ray photoemission and thermal desorption studies of a common linker molecule”
Radi, D. Pradhan, Y.K. Sohn, K.T. Leung, ACS Nano 4 (2010) 1553-60. “Nanoscale shape and size control of cubic, cuboctahedral, and octahedral Cu-Cu2O core-shell nanoparticles on Si(100) by one-step, templateless, capping-agent-free electrodeposition”
M. Ebrahimi, J.M. Chong, K.T. Leung, J. Phys. Chem. C 114 (2010) 2947-57. “Selective adsorption and thermal evolution of bifunctional carboxylic acids: Competition of O-H dissociation and other reaction products in acrylic acid and propanoic acid on Si(100)2×1″
D.U. Lee, D. Pradhan, R. Mouawia, D.H. Oh, N.F. Heinig, K.T. Leung, E. Prouzet, Chem. Mater. 22 (2010) 218-25. “ZnO nanostructures grown onto polypyrrole films prepared in swollen liquid crystals via integrative chemistry.”
D. Pradhan, S. Sindwani, K.T. Leung, J. Phys. Chem. C Letters 113 (2009) 15788-91. “Template-free electrochemical growth of single-crystalline zinc nanowires at an anomalously low temperature”
Youngku Sohn, Debabrata Pradhan, Abdullah Radi, K.T. Leung, Langmuir 25 (2009) 9557-63. “Interfacial electronic structure of gold nanoparticles on Si(100): Alloying versus quantum size effects”
D. Pradhan, K.T. Leung, J. Mater. Chem. Comm. 19 (2009) 4902-5. “Template-free single-step electrochemical synthesis of ZnO hollow nanospheres: Self-assembly of hollow nanospheres from nanoparticles”
H. Jalili, N.F. Heinig, K.T. Leung, Phys. Rev. B 79 (2009) 1-1_8. “X-ray photoemission study of Sr2FeMoO6 and SrMoO4 films epitaxially grown on MgO(001): Near-surface chemical-state composition analysis.”
M. Ebrahimi, K.T. Leung, Surf. Sci. 603 (2009) 1203-11. “Selective surface chemistry of allyl alcohol and allyl aldehyde on Si(100)2×1: Competition of [2+2] C=C cycloaddition with O-H dissociation and with [2+2] C=O cycloaddition in bifunctional molecules”
D. Pradhan, M. Kumar, Y. Ando, K.T. Leung, ACS Appl. Mat. Int. 1 (2009) 789-06. “Fabrication of ZnO nanospikes and nanopillars on ITO-glass by templateless seed-layer-free electrodeposition and their field emission properties.”
L. Zhang, A. Chatterjee, M. Ebrahimi, K.T. Leung, J. Chem. Phys. Comm. 130 (2009) 121103. “Hydrogen-bond mediated transitional adlayer of glycine on Si(111)7×7 at room temperature.” [Selected for the April 1, 2009 issue of Virtual Journal of Biological Physics Research]
M. Ebrahimi, J.F. Rios, K.T. Leung, J. Phys. Chem. C 113 (2009) 281-9. “Dissociative adsorption and thermal evolution of acetic acid on Si(100)2×1: Surface-mediated formation of ketene and acetaldehyde from unidentate and bidentate acetate adsorbates.”
H. Jalili, N.F. Heinig, K.T. Leung, J. Appl. Phys. 105 (2009) 034305-1_6. “Formation of nanocrystalline films of Sr2FeMoO6 on Si(100) by Pulsed Laser Deposition: Observation of preferential oriented growth.”
V. Venugopal, M. Ebrahimi, Z.H. He, K.T. Leung, Surf. Sci. 602 (2008) 3000-5. “Dissociative adsorption and thermal evolution of carbon tetrachloride on Si(111)7´7.”
Chatterjee, L.Y. Zhao, L. Zhang, D. Pradhan, X.J. Zhou, K.T. Leung, J. Chem. Phys. 129 (2008) 105104-1_6. “Core-level electronic structure of solid-phase glycine, glycyl-glycine, diglycyl-glycine and polyglycine: X-ray photoemission analysis and Hartree-Fock calculations of their zwitterions.” [Selected for the September 15, 2008 issue of Virtual Journal of Biological Physics Research]
D. Pradhan, K.T. Leung, Langmuir 24 (2008) 9707-16. “Controlled growth of two-dimensional and one-dimensional ZnO nanostructures on Indium Tin Oxide coated glass by direct electrodeposition”
D. Pradhan, M. Kumar, Y. Ando, K.T. Leung, J. Phys. Chem. C Letters 112 (2008) 7093-6. “One-dimensional and two-dimensional ZnO nanostructured materials on a plastic substrate and their field emission properties”
N.F. Heinig, N. Kharbanda, M.R. Pynenburg, X.J. Zhou, G.A. Scholz, K.T. Leung, Mater. Lett. 62 (2008) 2285-8. “The growth of nickel nanoparticles on conductive polymer composite electrodes.”
D. Pradhan, K.T. Leung, J. Phys. Chem. C 112 (2008) 1357-64. “Vertical growth of two-dimensional zinc oxide nanostructures on ITO-coated glass and its growth mechanism: Effects of deposition temperature and charge transfer”
D. Pradhan, M. Kumar, Y. Ando, K.T. Leung, Nanotechnology 19 (2008) 035603. “Efficient field emission from vertically grown ZnO nanowalls on ITO-glass substrate.” [Top 10% download of all IOP journals - 250 downloads in just 25 days]