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A. G. Unil Perera

Professor of Physics

Regents' Professor
Fellow, American Physical Society
Fellow, Society of Photoinstrumentation Engineers
Fellow, Institute of Electrical and Electronics Engineers
Department of Physics and Astronomy
Georgia State University
29 Peachtree Center Ave.
Science Annex, Rm 507
Atlanta, GA 30303
Phone: 404-413-6037


Research Description

The Semiconductor Optoelectronics laboratory focuses on developing novel semiconductor devices and applying infrared techniques to biochemical identifications. Novel device concepts, device physics, device design, modeling and experimental measurements, are performed in developing detectors for a wide wavelength range. Micro- and nanostructures based on III-V semiconductors including Arsenides, Phosphide, Antimonide, and Nitrides are some of the materials used in developing multiband and wavelength selectable detectors. Surface Plasmon, grating and other enhancements are considered in device optimizations. The main techniques used in the experimental studies include UV-VIS spectroscopy; Fourier Transform Infrared (FTIR) spectroscopy covering 0.2 μm to 1000 μm; attenuated total reflection measurements; Current-Voltage-Temperature (I-V-T); and Capacitance-Voltage-Temperature (C-V-T) measurements. Reflection, transmission, absorption and photoluminescence spectroscopy from UV to IR are regularly used to characterize the optical properties of semiconductors. Inter-band and inter-valence-band transitions, and the phonon structure in the far infrared are the typical parameters being investigated to support our detector development efforts. The temperature-dependent internal-photoemission spectroscopy (TDIPS) is developed in our lab to determine the band offsets of heterostructures and their temperature dependence. A magnet with a field up to 3.5 Tesla allows us to study Hall measurements and the effect of a magnetic field on the detectors. Few specific areas of interest are listed as follows:

  • Sensors and Nanotechnology
    • Quantum dot, ring and well Infrared photodetectors
    • Homo- and Heterojunction Interfacial Workfunction Internal Photoemission (HIWIP/HEIWIP) IR photodetectors
    • Dual- and Multi-Band Infrared photodetectors
    • Split-off Band Infrared photodetectors
    • Uncooled Infrared photodetectors
    • Dye Sensitized Semiconductor Nanostructure
  • Spectroscopic study of biological phenomena
    • Early detection of pathogenic infection in cells
    • Early detection of fungal infection in plants
  • Material characterizations
  • Non-linear dynamics associated with semiconductor devices
  • Infrared Emission