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)

    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.

    Professional Appointments

    • 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: 26-SEP-2014