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Beamteam Research Group

Research Area(s)

  • Graphene

Education

  • University of Saskatchewan
    Saskatoon, Saskatchewan
    B.E. Engineering Physics
    April 2003
  • University of Saskatchewan
    Saskatoon, Saskatchewan
    M.Sc. Physics
    January 2007
  • University of Saskatchewan
    Saskatoon, Saskatchewan
    Ph.D. Physics
    December 2013

Previous Affiliation

  • Science Associate, NSLS-II, Brookhaven National Lab

Ph.D. Thesis

  • The many mysteries of graphene oxide

Research Projects

Graphene

Graphene has been the focus of many researchers of late because it is the first stable two-dimensional crystal ever found. Graphene is simply carbon atoms in a honeycomb lattice, and is one layer of the more familiar graphite. Prior to the discovery of graphene, two-dimensional crystals were thought to be thermodynamically unstable and therefore impossible to find. The 2D nature of graphene gives it some very interesting properties, such as metallic-like conductivity and ballistic transport over macroscopic distances. Ballistic transport results when the mean free path of conduction electrons is on the order of micrometers or longer. If the length of a conduction device is shorter than the mean free path, the electron can pass through the device without ricocheting off the lattice, hence ballistic travel. Principally, this means zero resistance. This is a highly desirable property for nanodevices, because zero resistance means no parasitic energy losses or unwanted heat generation.

Graphite oxide is an excellent material with which to begin the study of graphene, because it can function as either a precursor material of graphene, via exfoliation and chemical reduction of individual graphene oxide sheets, or as a possible organic semiconductor material. However, one of the reasons why silicon-based semiconductors have formed the bedrock of modern electronics is that the band gap of silicon is easily and predictably changed by introducing the appropriate dopant. The band gap is simply the energy difference between the uppermost valence state to the lowermost conduction band state. In short, the band gap energy is the minimum energy one has to apply to an electron in the material to make it conduct. The band gap of a semiconductor is crucial to the function of computers, because it allows for two distinct logic states: "on" and "off", or "conducting" and "non-conducting". To function in the same capacity as silicon, graphite oxide must also have a suitably tuneable band gap.

The methods with which one may make graphite oxide are numerous. In the samples of interest here, the graphite bulk is supposedly oxidized with oxygen-containing functional groups. My research focuses on determining the band gap of different samples of graphite oxide as a function of synthesis technique using soft x-ray spectroscopy techniques. The underlying factors in the physical and electronic structures of the samples that ultimately determine the band gap will also be studied in detail. The types, concentrations, and distributions of the oxidizing functional groups as functions of synthesis method are questions of particular interest in the study of this material. Only with this understanding may the capabilities of graphite oxide be fully realized.

Awards

  • NSERC CGS D3 (September 2010)

Publications

  • Selective Area Band Engineering of Graphene using Cobalt-Mediated Oxidation    

  • P. Bazylewski, V.L. Nguyen, R.P.J. Bauer, A.H. Hunt, E.J.G. McDermott, B.D. Leedahl, A.I. Kukharenko, S.O. Cholakh, E.Z. Kurmaev, P. Blaha, A. Moewes, Y.H. Lee, G.S. Chang, Sci. Reports 5, 15380 (2015).

     

    The characterization of Co-nanoparticles supported on graphene

    P. Bazylewski, D. Boukhvalov, A.I. Kukharenko, E.Z. Kurmaev, A. Hunt, A. Moewes, Y.H. Lee, S.O. Cholakh, G.S. Chang, RSC Advances 5, 75600-75606 (2015).

     

    Pronounced, reversible, and in situ modification of the electronic structure of graphene oxide via cooling below 160 K  

    Hunt, E. McDermott, E.Z. Kurmaev, A. Moewes, J. Phys. Chem. Letters 6, 3163-3169 (2015).

     

    The electronic structure of Zirconium in hydrided and oxidized states 

    H. Akhiani, A Hunt, X. Cui, A. Moewes, J. Szpunar, J. Alloys & Compounds 622, 463-470 (2015).

     

    A Reevaluation of the Role of Functional Groups in Modifying the Electronic Structure of Graphene Oxide    

    A. Hunt, E.Z. Kurmaev, A. Moewes, Advanced Materials 26, 4870-4874 (2014).

     

    Band gap engineering of graphene oxide by chemical modification

    A. Hunt, E.Z. Kurmaev, A. Moewes, Carbon 75, 366-371 (2014).

     

    Modulation of the Band Gap of Graphene Oxide: The Role of AA-stacking

    A. Hunt, D.A. Dikin, E.Z. Kurmaev, Y.H. Lee, N.V. Luan, G.S. Chang, A. Moewes, Carbon 66, 539-545 (2014).

     

    Electronic Structure of Spinel Nitride Compounds Si3N4, Ge3N4 and Sn3N4 with Tunable Band Gaps: Application to Light Emitting Diodes   

    T.D. Boyko, A. Hunt, A. Zerr, A. Moewes, Phys. Rev. Lett. 111, 097402-1-5 (2013).

     

    The formation of Ti-O tetrahedra and band gap reduction in SiO2 via pulsed ion implantation    

    R.J. Green, D.A. Zatsepin, A. Hunt, E.Z. Kurmaev, N.V. Gavrilov, A. Moewes, J. Appl. Physics 113, 103704-1-4 (2013).

     

    Interplay of ballistic and chemical effects in the formation of structural defects for Sn and Pb implanted silica   

    R.J. Green, A. Hunt, D.A. Zatsepin, D.W. Boukhvalov, J.A. McLeod, E.Z. Kurmaev, N.A. Skorikov, N.V. Gavrilov, A. Moewes, J. Non-Cryst. Solids 358, 3187-3192 (2012).

     

    Epoxide Speciation and Functional Group Distribution in Graphene Oxide Paper-like Materials  

    A. Hunt, D.A. Dikin, E.Z. Kurmaev, T.D. Boyko, P. Bazylewski, G.S. Chang, A. Moewes, Advanced Functional Materials 22, 3950-3957 (2012).

     

    Formation of Mn-oxide clusters in Mn+-implanted SiO2 probed by soft X-ray emission and absorption spectroscopy 

    D.A. Zatsepin, A. Moewes, A. Hunt, N.V. Gavrilov, E.Z. Kurmaev, S.O. Cholakh, Vacuum 86, 1615-1617 (2012).

     

    Structural ordering in a silica glass matrix under Mn ion implantation   

    D.A. Zatsepin, R.J. Green, A. Hunt, E.Z. Kurmaev, N.V. Gavrilov, A. Moewes, J. Phys.: Cond. Matt. 24, 185402-1-7 (2012).

     

    Pb+ implanted SiO2 probed by soft X-ray emission and absorption spectroscopy

    D.Z. Zatsepin, A. Hunt, A. Moewes, E.Z. Kurmaev, N.V. Gavrilov, I.S. Zhidkov, S.O. Cholakh, Journal of Non-crystalline solids 357, 3381-3384 (2011).

     

    Solid versus solution: Examining the electronic structure of metallic DNA with soft X-ray spectroscopy and density functional theory    

    J.B. MacNaughton, M.V. Yablonskikh, A.H. Hunt, E.Z. Kurmaev, J.S. Lee, S.D. Wettig, A. Moewes, Phys. Rev. B 74, 125101-1-5 (2006).

     

    Electronic structures of LiFePO4 and FePO4 studied using resonant inelastic X-ray scattering   

    A. Hunt, W.-Y. Ching, Y.-M. Chiang, A. Moewes, Phys. Rev. B 73, 205120-1-10 (2006).

     

    Ion irradiation induced reduction of Fe3+ to Fe2+ in triethoxysilane films 

    R.G. Wilks, E.Z. Kurmaev, J.C. Pivin, A. Hunt, M.V. Yablonskikh, D.A. Zatsepin, A. Moewes, S. Shin, P. Palade, G. Principi, J. Phys.: Cond. Matt. 17, 7023-7028 (2005). 

     

    An indirect probe of the half-metallic nature of LiFePO4 using resonant inelastic X-ray scattering   

    A. Hunt, A. Moewes, W.-Y. Ching, Y.-M. Chiang, J. Phys. Chem. Sol. 66, 2290-2294 (2005).

     

    Studying 4d – 4f transitions in Er using resonant inelastic scattering

    A. Hunt, D. Muir, A. Moewes, J. Electr. Spectr. Rel. Phenom. 144-147, 573-576 (2005).