Sampath Gamage

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The influence of the growth temperature on the phase stability and composition of singlephase In1-xGaxN epilayers has been studied. The In1-xGaxN epilayers were grown by high-pressure Chemical Vapor Deposition with nominally composition of x = 0.6 at a reactor pressure of 15 bar at various growth temperatures. The layers were analyzed by x-ray diffraction,(More)
1 Department of Physics and Astronomy, Georgia State University, 29 Peachtree Center Ave, Atlanta, GA 30303, USA 2 Institut für Festkörperphysik, Technische Universität Berlin, Berlin, Germany 3 School of Electrical and Computer Engineering, Georgia Institute of Technology, Atlanta, GA 30332, USA 4 Dept. Electrical & Computer Engineering, University of(More)
A molecular beam epitaxy grown wavelength tunable GaAs p-i homojunction interfacial work-function internal photoemission far-infrared detector is developed. The multilayer (p-ip-i. . . ! detector structures consist of 2, 5, and 10 emitter layers. Experimental results are explained in terms of the number of emitter layers and the doping concentrations of the(More)
We have studied the formation of near-field fringes when sharp edges of materials are imaged using scattering-type scanning near-field optical microscope (s-SNOM). The materials we have investigated include dielectrics, metals, a near-perfect conductor, and those that possess anisotropic permittivity and hyperbolic dispersion. For our theoretical analysis,(More)
The appearance of stripe phases is a characteristic signature of strongly correlated quantum materials, and its origin in phase-changing materials has only recently been recognized as the result of the delicate balance between atomic and mesoscopic materials properties. A vanadium dioxide (VO2) single crystal is one such strongly correlated material with(More)
The influence of super-atmospheric reactor pressures (2.5-18.5 bar) on the electrical and structural properties of InN epilayers deposited on GaN/sapphire (0001) templates by high-pressure Chemical Vapor Deposition has been studied. The epilayers were analyzed by Raman, x-ray diffraction (XRD), and Fourier transform infrared reflectance spectrometry to(More)
We demonstrate dynamic reversible switching of VO2 insulator-to-metal transition (IMT) locally on the scale of 15 nm or less and control of nanoantennas, observed for the first time in the near-field. Using polarization-selective near-field imaging techniques, we simultaneously monitor the IMT in VO2 and the change of plasmons on gold infrared nanoantennas.(More)
Phase separations in ternary/multinary semiconductor alloys is a major challenge that limits optical and electronic internal device efficiency. We have found ubiquitous local phase separation in In1-xGaxN alloys that persists to nanoscale spatial extent by employing high-resolution nanoimaging technique. We lithographically patterned InN/sapphire substrates(More)
Black phosphorus (BP) possesses several extraordinary physical properties, which include in-plane anisotropy, thickness dependent direct bandgap and high carrier mobility. These physical properties make BP highly desirable from the point of view of fundamental science and modern optoelectronics applications. The excitement about this material has always(More)
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