Speaker: Prof. Ekmel Özbay, Nanotechnology Research Center, Bilkent University

Topic: "Metamaterial based nanobiosensors and nanophotodetectors"

Location: Middle East Technical University, Ankara, Turkey

Abstract: In this talk, we will present how metamaterials can be used for nanobiosensors and nanophotodetector applications. Our results show that a plasmonic structure can be successfully applied to bio-sensing applications and extended to the detection of specific bacteria species. A highly tunable design for obtaining double resonance substrates to be used in Surface Enhanced Raman Spectroscopy will also be presented. Surface Enhanced Raman Scattering experiments are conducted to compare the enhancements obtained from double resonance substrates to those obtained from single resonance gold truncated nano-cones. We will present a UV plasmonic antenna integrated metal semiconductor metal (MSM) photodetector based on GaN. We also report the design, fabrication, and measurement of a device comprising a split ring resonator array on epitaxial graphene. We obtained resonance broadening and tuning of split ring resonators by utilizing an epitaxial graphene transistor with transparent top-gate. Metallic split ring resonator (SRR) structures are used in nanophotonics applications in order to localize and enhance incident electromagnetic field. Electrically controllable sheet carrier concentration of graphene provides a platform where the resonance of the SRRs fabricated on graphene can be tuned. The reflectivity spectra of SRR arrays shift by applying gate voltage, which modulates the sheet carrier concentration, and thereby the optical conductivity of monolayer graphene. We experimentally and numerically demonstrated that the tuning range can be increased by tailoring the effective mode area of the SRR and enhancing the interaction with graphene.

Bio: Prof. Dr. Ekmel Ozbay received M.S. and Ph. D. degrees from Stanford University in electrical engineering, in 1989 and 1992. He worked as a postdoctoral research associate in Stanford University and he worked as a scientist in Iowa State University. He joined Bilkent University (Ankara, Turkey) in 1995, where he is currently a full professor in Physics Department and EEE Department. In 2003, he founded Bilkent University Nanotechnology Research Center (NANOTAM) where he leads a research group working on nanophotonics, nanometamaterials, nanoelectronics, GaN/AlGaN MOCVD growth, and GaN based devices. He is the 1997 recipient of the Adolph Lomb Medal of OSA and 2005 European Union Descartes Science award. He worked as an editor for Nature Scientific Reports, Optics Letters, PNFA, and IEEE JQE journals. He has published 430+ articles in SCI journals. His papers have received 13500+ SCI citations with an SCI h-index of 55. He has given 145+ invited talks in international conferences. He recently became the CEO of a spin-off company: AB-MicroNano Inc.

  Date and Time




  • Ankara, Ankara
  • Turkey
  • Co-sponsored by URSI-TR


Prof. Ekmel Özbay


Metamaterial based nanobiosensors and nanophotodetectors