Browsing by Author "Aktas, O."
Now showing items 1-11 of 11
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AlGaN/GaN HEMT-based fully monolithic X-band low noise amplifier
Schwindt, R.; Kumar, V.; Aktas, O.; Lee, J. W.; Adesida, I. (Wiley, 2005-04)A fully monolithic AlGaN/GaN HEMT-based low noise amplifier is reported. The circuit demonstrated a noise figure of 3.5 dB, gain of -7.5 dB, input return loss of -7.5 dB, and output return loss of -15 dB at 8.5 GHz. The ... -
Arrays of indefinitely long uniform nanowires and nanotubes
Yaman, M.; Khudiyev, T.; Ozgur E.; Kanik, M.; Aktas, O.; Ozgur, E. O.; Deniz, H.; Korkut, E.; Bayındır, Mehmet (Nature Publishing Group, 2011)Nanowires are arguably the most studied nanomaterial model to make functional devices and arrays. Although there is remarkable maturity in the chemical synthesis of complex nanowire structures, their integration and ... -
Design of a high-resolution microfluidic microwave MEMS phase shifter
Ozbey, B.; Ozturk, S.; Aktas, O. (Wiley, 2011)In this article, a novel microwave microelectromechanical phase shifter based on a microfluidic design is proposed and demonstrated. The design principles, the fabrication process, and experimental results (S-parameters ... -
Low damage etching of GaN surfaces via bias-assisted photoenhanced electrochemical oxidation in deionized water
Alptekin, E.; Yu, H.; Özbay, Ekmel; Aktas, O. (Springer New York LLC, 2007)Properties of GaN surfaces etched by bias-assisted photoenhanced electrochemical (PEC) oxidation in deionized water and subsequent removal of the oxidized material are investigated using Schottky diodes fabricated on etched ... -
Macroscopic assembly of indefinitely long and parallel nanowires into large area photodetection circuitry
Ozgur E.; Aktas, O.; Kanik, M.; Yaman, M.; Bayındır, Mehmet (American Chemical Society, 2012)Integration of nanowires into functional devices with high yields and good reliability turned out to be a lot more challenging and proved to be a critical issue obstructing the wide application of nanowire-based devices ... -
Nanoscale charging hysteresis measurement by multifrequency electrostatic force spectroscopy, insulating substrates, silicon nanocrystals
Bostanci, U.; Abak, M. K.; Aktas, O.; Dana, A. (American Institute of Physics, 2008-03-04)We report a scanning probe technique that can be used to measure charging of localized states on conducting or partially insulating substrates at room temperature under ambient conditions. Electrostatic interactions in the ... -
A new route for fabricating on-chip chalcogenide microcavity resonator arrays
Aktas, O.; Ozgur E.; Tobail, O.; Kanik, M.; Huseyinoglu, E.; Bayındır, Mehmet (Wiley-VCH Verlag, 2014-07)High-yield production and on-chip integration of high-Q chalcogenide microresonators with various sizes and geometrical shapes (spherical, spheroidal, and ellipsoidal) and with sub-nanometer surface roughness is achieved. ... -
Parametrically coupled multiharmonic force imaging
Abak, M. K.; Aktas, O.; Mammadov R.; Gürsel, I.; Dâna, A. (AIP Publishing, 2008)We report use of nonlinear tip-sample interactions to parametrically convert the frequency components of periodic tip-sample interaction forces to frequencies where they can be resonantly detected. One flexural mode of a ... -
Simulation of GaN and AlGaN static induction transistors
Alptekin, E.; Aktas, O. (Elsevier Science & Technology, 2006)GaN and AlGaN static induction transistors (SITs) are simulated using a two-dimensional self-consistent drift-diffusion simulator incorporating impact-ionization and self-heating effects. The results indicate that GaN SIT ... -
Spontaneous high piezoelectricity in poly ( vinylidene fluoride ) nanoribbons produced by iterative thermal size reduction technique
Kanik, M.; Aktas, O.; Sen, H. S.; Durgun, Engin; Bayındır, Mehmet (American Chemical Society, 2014-08-18)We produced kilometer-long, endlessly parallel, spontaneously piezoelectric and thermally stable poly(vinylidene fluoride) (PVDF) micro- and nanoribbons using iterative size reduction technique based on thermal fiber ... -
Transient surface photovoltage in n-and p-GaN as probed by x-ray photoelectron spectroscopy
Sezen, H.; Özbay, Ekmel; Aktas, O.; Süzer, Şefik (2011)Transient surface photovoltage (SPV) of n and p-GaN was measured using x-ray photoelectron spectroscopy (XPS) with a time resolution of 0.1 s. The measured SPV transients for both n- and p-GaN are 0.1 s, and for the n-GaN ...