Tuning Silicon Photonic Crystal Band Gap by Oxidation and Etching.

ORAL

Abstract

Tunability of photonic bandgap is restricted by the limited number of parameters that can be varied. In triangular silicon photonic crystal consisting of silicon pillars in air background, it is difficult to fine tune the photonic band gap because the gap is too sensitive to the change in atom radius. When silicon atom is etched from the radius of 0.28*a (a = lattice constant), to 0.1* a, the TM band gap drastically changes from 0.095 to 0.16 normalized frequency value, and the midgap frequency shifts from 0.325 to 0.49. In this paper it is demonstrated that by oxidizing the silicon and etching the silicon dioxide, the band gap can be tuned in a much finer scale by varying the oxide thickness. Plane wave expansion method is used for modeling the process. In our model, when silicon pillars are oxidized so that silicon is consumed and silicon radius goes from 0.28*a to 0.1*a, the band gap changes very slowly from 0.095 to 0.1 and the midgap from 0.325 to 0.42. After that the silicon dioxide is etched, and the band gap and midgap frequency changes slowly with the oxide thickness. Along this path the band gap moves from 0.1 to 0.16 and the midgap frequency from 0.42 to 0.49.

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Authors

  • Makhin Thitsa

  • J. Deng

    US Naval Observatory, University of Virginia, Thomas Jefferson National Accelerator Facility, College of William and Mary, US Army Research Office, Brimrose Corporation of America, Hampton University, Department of Physics, University of Rajshahi, Rajshahi, Bangladesh, Department of Physics, Old Dominion University, Norfolk, VA 23529, University of North Carolina at Chapel Hill, Department of Physics, Old Dominion University, Norfolk, Virginia, Department of Physics, Korea University, Seoul, Korea, Department of Physics, University of Virginia, Charlottesville, VA, Department of Physics, Old Dominion University, Norfolk, VA, North Carolina State University and WebAssign, Raleigh, NC, North Carolina State University, Raleigh, NC, Broughton High School, Raleigh, NC, University of Wisconsin at Whitewater, Whitewater, WI, University of North Carolina-Chapel Hill Department of Physics, University of West Virginia - Chemistry Dept., ORNL, Old Dominion University, University of West Virginia Department of Chemistry, Clemson University, South Carolina Governor’s School for Science and Mathematics, College of Charleston, Rice University, Korea Research Institute of Standards and Science, Ohio State University, Wright State University, Yale U, JINR, Dubna, Univ. Fed. do Rio de Janeiro, Vanderbilt Univ./JIHIR(ORNL)/Tsinghua Univ., NSCL(MSU), LLNL, LBNL, Vanderbilt Univ./LBNL/JIHIR(ORNL), Vanderbilt Univ., Jagellonian University, University of Bonn, North Carolina A{\&T} State University, North Carolina Central University, Duke University and TUNL