Institute of High Performance Computing

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Electronics & Photonics (EP)

Dr. KOH Wee Shing

Dr. KOH Wee Shing


Research Interests:

  • Nano-Photonics and Plasmonics
  • Solar cell design and Optoelectronic device physics
  • Plasma and particle-in-cell simulations
  • Urban environmental & green building modeling - solar irradiance & daylighting

Qualifications:

  • PhD., Electrical and Electronic Engineering, Nanyang Technological University, Singapore, 2007
  • B.Eng. (Honours), Electrical and Electronic Engineering, Nanyang Technological University, 2002

Published Journals/ Articles:

Journals

    • Y.-L. Liu, S. H. Chen, W. S. Koh, and L. K. Ang, “Two-dimensional relativistic space charge limited current flow in the drift space", Phys. Plasmas, 21, 043101 (2014).
    • W. S. Koh, C. H. Gan, W. K. Phua, Yu. A. Akimov and P. Bai, “The potential of graphene as an ITO replacement in organic solar cells: An optical perspective”, IEEE J. Quantum Electron., 20, 36-42 (2014).
    • W. J. Ding, Z. M. Sheng and W. S. Koh, “High-field half-cycle terahertz radiation from relativistic laser interaction with thin solid targets”, Applied Physics Letters, 103, 204107 (2013).
    • S. H. Chen, L. C. Tai, Y. L. Liu, L. K. Ang, and W. S. Koh, “Two-dimensional electromagnetic Child–Langmuir law of a short-pulse electron flow", Phys. Plasmas, 18, 023105 (2011).
    • Yu. A. Akimov and W. S. Koh, “Design of plasmonic nanoparticles for efficient subwavelength light trapping", Appl. Phys. Let., 99, 063102 (2011).
    • Yu. A. Akimov and W. S. Koh, “Tolerance sudy of nanoparticle enhancement for thin-film silicon solar cell", Appl. Phys. Let., 99, 063102 (2011).
    • W. S. Koh, M. Pant, Yu. A. Akimov, W. P. Goh and Y. Li, “Three-Dimensional Optoelectronic Model for Organic Bulk Heterojunction Solar Cells, IEEE Journal of Photovoltaics, 1, 84-92 (2011).
    • Wee Shing Koh and Yu. A. Akimov, “Solar & Alternative Energy: Enhanced light trapping in thin-film solar cells”, SPIE Newsroom(31 Mar 2010). [INVITED ARTICLE]
    • O. Kurniawan, M. F. Ng, W. S. Koh, Z. Y. Leong, E. Li, “Simplified model for ballistic current-voltage characteristic in cylindrical nanowires”, Microelectronics Journal 41, 155-161 (2010).
    • L. Wu, H. S. Chu, W. S. Koh and E. P. Li, “Highly sensitive graphene biosensors based on surface plasmon resonance", Optics Express, 18, 14395 (2010).
    • Yu. A. Akimov and W. S. Koh, “Resonant and nonresonant plasmonic nanoparticle enhancement for thin-film silicon solar cells", Nanotechnology, 21, 235201 (2010).
    • Yu. A. Akimov, W. S. Koh, S. Y. Sian and S. Ren, “Nanoparticle-enhanced thin film solar cells: Metallic or dielectric nanoparticles?", Appl. Phys. Lett., 96, 073111 (2010).
    • Yu. A. Akimov, W. S. Koh and K. Ostrikov, “Enhancement of optical absorption in thin-film solar cells through the excitation of higher-order nanoparticle plasmon modes", Opt. Exp., 17, 10195-10205 (2009).
    • W. Chandra, L. K. Ang, and W. S. Koh, “Two-dimensional model of space charge limited electron injection into a diode with Schottky contact", J. Phys. D: Appl. Phys., 42, 055504 (2009).
    • W. S. Koh, and L. K. Ang, “Quantum model of space-charge-limited field emission in a nanogap”, Nanotechnology, 19, 235402 (2008).
    • L. Wu, L. K. Ang and W. S. Koh, “Theory of shot noise in high-current space-charge-limited field emission”, Physical Review B, 77, 115351 (2008).
    • P. Bai, E. Li, K. T. Lam, O. Kurniawan, and W. S. Koh, “Carbon nanotube Schottky diode: an atomic perspective”, Nanotechnology, 19, 115203 (2008).
    • H. S. Chu, W. B. Ewe, W. S. Koh, and E. P. Li, “Remarkable influence of the number of nanowires on plasmonic behaviors of the coupled metallic nanowire chain”, Appl. Phys. Lett., 92, 103103 (2008).
    • W. S. Koh, and L. K. Ang, “Two-dimensional space-charge-limited flow in a crossed-field gap”, Appl. Phys. Lett., 90, 141503 (2007).
    • W. S. Koh, L. K. Ang, S. P. Lau and T. J. T. Kwan, "Transition of field emission to space-charge-limited emission in a nanogap, Appl. Phys. Lett., 89, 183107 (2006).
    • W. S. Koh, L. K. Ang, S. P. Lau and T. J. T. Kwan, "Multi-dimensional Short-pulse Space-charge-limited Flow”, Phys. Plasmas, 13, 063102 (2006)
    • L. K. Ang, W. S. Koh, Y. Y. Lau and T. J. T. Kwan, "Space-charge-limited flows in the quantum regime", Physics of Plasmas, 13, 056701 (2006) [INVITED PAPER]
    • W. S. Koh, L. K. Ang, S. P. Lau and T. J. T. Kwan, "Space-charge-limited bipolar flow in a nano-gap", Applied Physics Letters, 87, 193112 (2005).
    • W. S. Koh, L. K. Ang and T. J. T. Kwan, "Three-Dimensional Child-Langmuir Law for hot electron emission", Physics of Plasmas, 12, 053107 (2005).
    • W. S. Koh and L. K Ang, “Simulation of high current field emission from vertically well-aligned metallic carbon nanotubes”, International Journal of Nanoscience 3 , 677-684 (2004).

Conferences

    • W. S. Koh, “Generation and controlof strong half cycle THz radiationwith ultrashort laser", The 41st IEEE International Conference on Plasma Science (ICOPS) and the 20th International Conference on High-Power Particle Beams (BEAMS), Washington DC, USA, 25-29 May 2014, Contrib. 5B-8.
    • W. J. Ding, W. S. Koh, “Numerical thermalization of two-dimensional plasmas in the presence of binary collisions with the particle-in-cell method", The 41st IEEE International Conference on Plasma Science (ICOPS) and the 20th International Conference on High-Power Particle Beams (BEAMS), Washington DC, USA, 25-29 May 2014, Contrib. 2A-1. (INVITED)
    • W. S. Koh, “Particle-in-cell simulations for laser-plasma applications", International Conference on Plasma Science and Applications (ICPSA2013), Singapore, 4-6 Dec 2013, Contrib. I44. (INVITED)
    • W. J. Ding, W. S. Koh, and , Z. M. Sheng, “Intense THz radiation by laser illuminated solid targets", IEEE Pulsed Power and Plasma Science Conference (PPPS), San Franciso, USA, 16-21 Jun 2013, Contrib. 10E-3.
    • Y. L. Liu, S. H. Chen and W. S. Koh, “Two-Dimensional Space Charged Limiting Current Density of a Long-Pulse Electron Flow in Drift Space", IEEE Pulsed Power and Plasma Science Conference (PPPS), San Franciso, USA, 16-21 Jun 2013, Contrib. 5F-8.
    • W. J. Ding and W. S. Koh, “Development of Particle-in-Cell Codes at IHPC", IEEE Pulsed Power and Plasma Science Conference (PPPS), San Franciso, USA, 16-21 Jun 2013, Contrib. P4-5.
    • W.S. Koh, Yu. A. Akimov, and W. P. Goh “3D full-wave optical and electronic modeling of organic bulk-heterojunction solar cells: A predictive approach”, SPIE Photonics West, San Francisco, USA, 2-7 Feb 2013, OPTO & Green Photonics Symposium, Contrib. 8619-43.
    • W. S. Koh, S. H. Chen and L. K. Ang, “Plasma for plasmonics", The 39th IEEE International Conference on Plasma Science Conference (ICOPS), Edinburgh, UK, 8-12 Jul 2012, Contrib. 3P-28.
    • W. J. Ding, B. Hao, Z. M. Sheng, C. Ren and W. S. Koh, “Plasma for plasmonics", The 39th IEEE International Conference on Plasma Science Conference (ICOPS), Edinburgh, UK, 8-12 Jul 2012, Contrib. 1P-180.
    • W. S. Koh, M. Pant, Yu. A. Akimov, and W. P. Goh, “Device modeling for organic bulk heterojunction solar cell”, International Conference on Materials for Advanced Technologies (ICMAT 2011), Singapore, 26 June - 1 July 2011. Symposium R: Flexible Electronics Materials and Device Physics, Contrib. R4-7.
    • W. S. Koh, S. H. Chen, L. K. Ang, “Particle-in-cell simulation of plasmonic nanoparticle", The 38th IEEE International Conference on Plasma Science Conference (ICOPS) and 24th Symposium on Fusion Engineering (SOFE), Chicago, USA, 26-30 Jun 2011, Contrib. IP2B-11.
    • Y. L. Liu, L. C. Tai, S. H. Chen, L. K. Ang and W. S. Koh, “Two-dimensional electromagnetic Child-Langmuir law of a short-pulse electron flow", 2011 IEEE International Vacuum Electronics Conference (IVEC), Bangalore, India, 21-24 Feb 2011, Contrib. 419-420.
    • Yu. A. Akimov and W. S. Koh, “Optimization of light-trapping in thin-film solar cells enhanced with plasmonic nanoparticles”, Photonics Global Conference 2010, Singapore, 14-16 December 2010, Contrib. 2-2D-5.
    • M. Pant, L. K. Ang and W. S. Koh, "Quantum shot noise reduction for electron field emission from different shapes", 2010 8th International Vacuum Electron Sources Conference and Nanocarbon (IVESC), Nanjing, China, 14-16 Oct 2010, Contrib. 266-267.
    • S. Sun, L. K. Ang and W. S. Koh, "Space charge limited field emission from a single sharp field emitter", 2010 8th International Vacuum Electron Sources Conference and Nanocarbon (IVESC), Nanjing, China, 14-16 Oct 2010, Contrib. 152-153.
    • W. Chandra, L. K. Ang and W. S. Koh, "High current electron emission and injection in a gap with both vacuum and solid", 2010 8th International Vacuum Electron Sources Conference and Nanocarbon (IVESC), Nanjing, China, 14-16 Oct 2010, Contrib. 37-38.
    • W. S. Koh, Yu.A. Akimov, Y. Li, M.S. Soh, W.P. Goh, and H.S. Chu, "Optical enhancement with plasmonic nanoparticles in organic bulk-heterojunction solar cells", Imaging and Applied Optics: OSA Optics & Photonics Congress, Tucson, USA, 7-9 June 2010, Topical Meeting: Optics for Solar Energy, Contrib. SWA3.
    • Yu. A. Akimov, W. S. Koh, and E. P. Li, "Surface plasmon enhancement of thin-film amorphous silicon solar cells", International Conference on Materials for Advanced Technologies (ICMAT 2009), Singapore, 29 Jun-3 Jul 2009, Symposium G: Plasmonics and Applications, Book of Abstracts, p. 9.
    • Yu. A. Akimov and W. S. Koh, "Plasmon-enhanced light absorption in thin-film amorphous silicon solar cells", 34th IEEE Photovoltaic Specialists Conference (PVSC), Philadelphia, USA, 7-12 Jun 2009, Contrib. BQ4-101.
    • W. S. Koh, L. C. Tai, S. H. Chen and L. K. Ang, “Modeling of longtitudinual spacecharge-effects for the monoenergetic electron beam in a laser wakefield accelerator", The 35th IEEE International Conference on Plasma Science Conference (ICOPS) and 23rd Symposium on Fusion Engineering (SOFE), San Diego, USA, 1-5 Jun 2009, Contrib.
    • L. C. Tai, P. Zhang, W. S. Koh, L. K. Ang and S. H. Chen, “The Effect of the Self-Magnetic Field on the Current Limit in a Laser Wakefield Accelerator (LWFA)", American Physical Society (APS) Meeting, 50th Annual Meeting of the Division of Plasma Physics, Dallas, USA, 17-21 Nov 2008 , Contrib. PP6.00056.
    • L. Wu, L. K. Ang and W. S. Koh, “Nonequilibrium model of ultrafast laser induced electron emission from a dc-biased metallic surface", American Physical Society (APS) Meeting, 50th Annual Meeting of the Division of Plasma Physics, Dallas, USA, 17-21 Nov 2008 , Contrib. TO3.00006.
    • W. S. Koh, L. K. Ang, S. H. Chen, L. C. Tai and L. Wu, “2D limiting current of a finite-width electron pulse in a parallel-plate gap", American Physical Society (APS) Meeting, 50th Annual Meeting of the Division of Plasma Physics, Dallas, USA, 17-21 Nov 2008 , Contrib. UP6.00083.
    • L. Wu, L. K. Ang and W. S. Koh, “Low temperature refrigeration by using thermal-field emission in a coaxial cylindrical diode", American Physical Society (APS) Meeting, 50th Annual Meeting of the Division of Plasma Physics, Dallas, USA, 17-21 Nov 2008 , Contrib. YP6.00055.
    • P. Zhang, W. S. Koh and L. K. Ang, “Space-charge-limited electron flow in a drift space", The 34th IEEE International Conference on Plasma Science and the 16th IEEE International Pulsed Power Conference, Albuquerque , USA, 17-22 Jun 2007, Contrib. 528.
    • W. S. Koh and L. K. Ang, “Influence of Image Charge Potential on High Current Field Emitted Electron Flows in a Nano-Diode", The 34th IEEE International Conference on Plasma Science and the 16th IEEE International Pulsed Power Conference, Albuquerque , USA, 17-22 Jun 2007, Contrib. 646.
    • W. S. Koh, L. K. Ang, L. Sun and X. Hua, “Two-dimensional limiting current in crossed-field gap", 2006 International Vacuum Nanoelectronics Conference (IVNC) and the 2006 50th International Field Emission Symposium (IFES). Technical Digest. 19th International, Guilin, China, 17-22 Jun 2007, Contrib. 197-198.
    • W. S. Koh and L. K. Ang, “Transition from Fowler-Nordheim to Child-Langmuir Law in the quantum regime", 2006 International Vacuum Nanoelectronics Conference (IVNC) and the 2006 50th International Field Emission Symposium (IFES). Technical Digest. 19th International, Guilin, China, 17-22 Jun 2007, Contrib. 13-14.
    • W. S. Koh, L. K. Ang, L. Sun and X. Hua, “Multi-dimensional child-langmuir law for a crossed-field gap", The 33rd IEEE International Conference on Plasma Science, Traverse City, USA, 4-6 Jun 2006, Contrib. 113.
    • W. S. Koh and L. K. Ang, “Cylindrical short-pulse Child-Langmuir law", American Physical Society (APS) Meeting, 47th Annual Meeting of the Division of Plasma Physics, Denver, USA, 24-28 Oct 2005 , Contrib. BP1.00094.
    • W. S. Koh and L. K. Ang, “Two-Dimensional Short-Pulse Child-Langmuir Law", The 32nd IEEE International Conference on Plasma Science, Monterey, USA, 20-23 Jun 2005, Contrib. 298.
    • W. S. Koh and L. K. Ang, “Bipolar Quantum Child-Langmuir Law", The 32nd IEEE International Conference on Plasma Science, Monterey, USA, 20-23 Jun 2005, Contrib. 98.
    • W. S. Koh and L. K. Ang, “3D model of Child-Langmuir law", The 31st IEEE International Conference on Plasma Science, Baltimore, USA, 28 Jun-1 Jul 2004, Contrib. 283.

Other(s)

    Technical Leadership

    • Project Manager, Industry Collaboration Project on "Empirical Engineering Data Modeling". Funding: S$141,500 for 1 year (Sep 2014-Aug 2015).
    • Co-Principal Investigator, "Development of Integrated Multiphysics Urban Microclimatic Modelling Tool - Wind and Thermal, Solar Irradiance/Shading and Acoustic Noise Mapping", Land and Liveability National Innovation Challenge (L2 NIC) funded by the Ministry of National Development (MND) and National Research Foundation (NRF), Prime Minister"s Office, Singapore. Award No: L2NICCFP1-2013-6. Funding: S$2,986,434 for 3 years (Nov 2014 - Oct 2017).

    Invited Talks

    • W. S. Koh, "Modeling Laser-Metal Interactions with the Particle-In-Cell Method", sponsored by IEEE Victoria Section, University of Victoria, 26 Apr 2013.
    • W. S. Koh,"Three-dimensional Optoelectronic Model for Organic Photovoltaics", IMRE - Hong Kong Baptist University "Advances in Organic Electronics Workshop", Singapore, 12 Jan 2011.

    Invited Outreach

    • W. S. Koh, " The REAL BEGINNING after PhD - A computational scientist point of view", 4th National University of Singapore Graduate Student Symposium, 16 Jan 2012.
    • W. S. Koh, Panellist for Opportunities Talk (Industry Session), 4th National University of Singapore Graduate Student Symposium, 16 Jan 2012.

    Technical and Professional Appointments

    • Ad hoc Reviewer, National Science Foundation (NSF), International Research Fellowship Program (IRFP), USA, 2011-2012.
    • Grant Reviewer, A*STAR SERC INFUSE Exploratory Grant, 2011.
    • Visiting Scientist to Physics Department, National Central University, Taiwan, from 2008-present
    • Visiting Scientist to Center for Photovoltaics, National Renewable Laboratory, USA in 2010
    • Elected Council Member, Institute of Physics Singapore, from 2012-present
    • Elected Chair, IEEE Nuclear and Plasma Science Society, Singapore Chapter, from 2014 - present


This page is last updated at: 03-OCT-2014