Sujeewa De Silva received her B.Sc in Materials Engineering (2003) with 1st class honours from the University of Moratuwa, Sri Lanka. After having an exposure on the research and development work at a world known porcelain manufacturing company, she joined the department of Materials Science, University of Moratuwa as a lecturer (2005). Few years later, she moved to Australia to pursue her PhD studies at the University of Wollongong, under the supervision of Prof. Shi X. Dou. Her PhD research was on “Investigating and improving the properties of graphene doped magnesium diboride superconductors”. On completion of her studies, she worked at Institute for superconducting and electronic materials (ISEM), UoW as a research fellow continued her work on magnesium diboride superconductors. She joined the School of Physics and Advanced Materials at UTS in January 2014 as a postdoctoral fellow to work on the synthesis of precious metals and intermetallic compounds, and their optical properties.
Can supervise: YES
Synthesis of precious metals and intermetallic compounds, and investigate their optical properties.
Optical properties of nanostructures
Subject coordinator :
Chemistry and Materials Science (60101)
Introduction to Materials (68070)
De Silva, KSB & Xu, X 2013, Graphene/Graphene oxide doped magnesium diboride superconductors, 1, LAP LAMBERT Academic Publishing, Germany.
De Silva, KSB, Keast, VJ, Gentle, A & Cortie, MB 2017, 'Optical properties and oxidation of α-phase Ag-Al thin films.', Nanotechnology, vol. 28, no. 9, pp. 095202-095202.View/Download from: Publisher's site
We investigate a series of Ag-Al thin films containing up to 12 at% Al with the purpose of discovering whether these alloys would be a better choice for nanophotonic applications than pure Ag. Variable angle spectroscopic ellipsometry, AFM, x-ray diffraction and density functional theory are applied to explore and characterize the materials. Electromagnetic simulations of optical properties are used to place the results into a theoretical framework. We find that the increase in electron-to-atom ratio associated with the Al additions changes the optical properties: additions of the order of 1-2 at% Al are beneficial as they are associated with favorable changes in the dielectric function, but for greater additions of Al there is a flattening of the absorption edge and an increase in optical loss. In addition, contents of more than about 2 at% Al are associated with the onset of time-dependent intergranular oxidation, which causes a pronounced dip in the reflectance spectrum at about 2.3-2.4 eV (∼500-540 nm).
De Silva, KSB, Keast, VJ & Cortie, MB 2016, 'Effect of Al additions on the optical properties of Au alpha-phase', JOURNAL OF ALLOYS AND COMPOUNDS, vol. 679, pp. 225-230.View/Download from: Publisher's site
De Silva, KSB, Gentle, A, Arnold, M, Keast, VJ & Cortie, MB 2015, 'Dielectric function and its predicted effect on localized plasmon resonances of equiatomic Au-Cu', Journal of Physics D: Applied Physics, vol. 48, no. 21.View/Download from: Publisher's site
Equiatomic (Au,Cu) solid solution orders below 658 K to form a tetragonal AuCu (I) phase with significant changes in physical properties and the crystal structure. The effect of ordering on the dielectric function of the material is controversial however, with inconsistent results reported in the literature. Since the nature of any localized surface plasmon resonance (LSPR) in the nanostructures is very sensitive to the dielectric function, this uncertainty hinders the use of AuCu in plasmonic devices or structures. Therefore, we re-examine the question using a combination of measurements and computations. We find that no significant change in the dielectric function occurs when this material becomes ordered, at least over the range of photon energies relevant to LSPRs. The likely properties of LSPRs in plasmonic devices made of AuCu are analyzed. Use of the alloy offers some advantages over pure Cu, however pure Au would still be the superior option in most situations.
Keast, VJ, Ewald, J, De Silva, KSB, Cortie, MB, Monnier, B, Cuskelly, D & Kisi, EH 2015, 'Optical properties and electronic structure of the Cu-Zn brasses', JOURNAL OF ALLOYS AND COMPOUNDS, vol. 647, pp. 129-135.View/Download from: Publisher's site
Mustapic, M, De Silva, KSB, Aboutalebi, SH, Barua, S, Xu, X, Wang, J, Hossain, MS, Horvat, J & Dou, SX 2015, 'Improvements in the Dispersion of Nanosilver in a MgB2 Matrix through a Graphene Oxide Net', JOURNAL OF PHYSICAL CHEMISTRY C, vol. 119, no. 19, pp. 10631-10640.View/Download from: Publisher's site
Tai, MC, Gentle, A, de Silva, KSB, Arnold, MD, van der Lingen, E & Cortie, MB 2015, 'Thermal Stability of Nanoporous Raney Gold Catalyst', METALS, vol. 5, no. 3, pp. 1197-1211.View/Download from: Publisher's site
Wong, DCK, Yeoh, WK, De Silva, KSB, Kondyurin, A, Bao, P, Li, WX, Xu, X, Peleckis, G, Dou, SX, Ringer, SP & Zheng, RK 2015, 'Microscopic unravelling of nano-carbon doping in MgB2 superconductors fabricated by diffusion method', JOURNAL OF ALLOYS AND COMPOUNDS, vol. 644, pp. 900-905.View/Download from: Publisher's site
Wong, DCK, Yeoh, WK, Trimby, PW, De Silva, KSB, Bao, P, Li, WX, Xu, X, Dou, SX, Ringer, SP & Zheng, RK 2015, 'Characterisation of nano-grains in MgB2 superconductors by transmission Kikuchi diffraction', SCRIPTA MATERIALIA, vol. 101, pp. 36-39.View/Download from: Publisher's site
Yeoh, WK, Cui, XY, Gault, B, De Silva, KSB, Xu, X, Liu, HW, Yen, H-W, Wong, D, Bao, P, Larson, DJ, Martin, I, Li, WX, Zheng, RK, Wang, XL, Dou, SX & Ringer, SP 2014, 'On the roles of graphene oxide doping for enhanced supercurrent in MgB2 based superconductors.', Nanoscale, vol. 6, no. 11, pp. 6166-6172.View/Download from: Publisher's site
Due to their graphene-like properties after oxygen reduction, incorporation of graphene oxide (GO) sheets into correlated-electron materials offers a new pathway for tailoring their properties. Fabricating GO nanocomposites with polycrystalline MgB2 superconductors leads to an order of magnitude enhancement of the supercurrent at 5 K/8 T and 20 K/4 T. Herein, we introduce a novel experimental approach to overcome the formidable challenge of performing quantitative microscopy and microanalysis of such composites, so as to unveil how GO doping influences the structure and hence the material properties. Atom probe microscopy and electron microscopy were used to directly image the GO within the MgB2, and we combined these data with computational simulations to derive the property-enhancing mechanisms. Our results reveal synergetic effects of GO, namely, via localized atomic (carbon and oxygen) doping as well as texturing of the crystals, which provide both inter- and intra-granular flux pinning. This study opens up new insights into how low-dimensional nanostructures can be integrated into composites to modify the overall properties, using a methodology amenable to a wide range of applications.
Chen, SK, Tan, KY, Halim, AS, Xu, X, De Silva, KSB, Yeoh, WK, Dou, SX, Kursumovic, A & MacManus-Driscoll, JL 2013, 'Reaction method control of impurity scattering in C-doped MgB2: proving the role of defects besides C substitution level', SUPERCONDUCTOR SCIENCE & TECHNOLOGY, vol. 26, no. 12.View/Download from: Publisher's site
De Silva, KSB, Aboutalebi, SH, Xu, X, Wang, XL, Li, WX, Konstantinov, K & Dou, SX 2013, 'A significant improvement in both low- and high-field performance of MgB2 superconductors through graphene oxide doping', SCRIPTA MATERIALIA, vol. 69, no. 6, pp. 437-440.View/Download from: Publisher's site
De Silva, KSB, Xu, X, Gambir, S, Wong, DCK, Li, WX & Hu, QY 2013, 'Effect of Sintering Temperature on the Superconducting Properties of Graphene Doped MgB2', IEEE TRANSACTIONS ON APPLIED SUPERCONDUCTIVITY, vol. 23, no. 3.View/Download from: Publisher's site
Li, WX, Xu, X, De Silva, KSB, Xiang, FX & Dou, SX 2013, 'Graphene Micro-Substrate Induced High Electron-Phonon Coupling in MgB2', IEEE TRANSACTIONS ON APPLIED SUPERCONDUCTIVITY, vol. 23, no. 3.View/Download from: Publisher's site
Xiang, FX, Wang, XL, Xun, X, De Silva, KSB, Wang, YX & Dou, SX 2013, 'Evidence for transformation from delta T-c to delta l pinning in MgB2 by graphene oxide doping with improved low and high field J(c) and pinning potential', APPLIED PHYSICS LETTERS, vol. 102, no. 15.View/Download from: Publisher's site
De Silva, KSB, Gambhir, S, Wang, XL, Xu, X, Li, WX, Officer, DL, Wexler, D, Wallace, GG & Dou, SX 2012, 'The effect of reduced graphene oxide addition on the superconductivity of MgB2', JOURNAL OF MATERIALS CHEMISTRY, vol. 22, no. 28, pp. 13941-13946.View/Download from: Publisher's site
De Silva, KSB, Xu, X, Wang, XL, Wexler, D, Attard, D, Xiang, F & Dou, SX 2012, 'A significant improvement in the superconducting properties of MgB2 by co-doping with graphene and nano-SiC', SCRIPTA MATERIALIA, vol. 67, no. 10, pp. 802-805.View/Download from: Publisher's site
Xu, X, Li, WX, Zhang, Y, De Silva, KSB, Kim, JH & Choi, S 2012, 'The Effects of Graphene Doping on the In-Field J(c) of MgB2 Wires', JOURNAL OF NANOSCIENCE AND NANOTECHNOLOGY, vol. 12, no. 2, pp. 1402-1405.View/Download from: Publisher's site
De Silva, KSB, Xu, X, Gambhir, S, Wang, XL, Li, WX, Wallace, GG & Dou, SX 2011, 'Flux pinning mechanisms in graphene-doped MgB2 superconductors', SCRIPTA MATERIALIA, vol. 65, no. 7, pp. 634-637.View/Download from: Publisher's site