Browsing by Author "Toprak, Ahmet"
Now showing items 1-10 of 10
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Colorimetric and near-absolute polarization-insensitive refractive-index sensing in all-dielectric guided-mode resonance based metasurface
(American Chemical Society, 2019)Colorimetric detection of target molecules with insensitivity to incident-light polarization has attracted considerable attention in recent years. This resulted from the ability to provide rapid output and reduced assay ... -
Disordered and densely packed ITO nanorods as an excellent lithography-free optical solar reflector metasurface
(American Chemical Society, 2019)Precise control and stabilization of the operating temperature environment of spacecraft and satellites during their life cycle is of paramount importance to increase device reliabilities and reduce the thermomechanical ... -
Disordered and densely packed ITO nanorods as an excellent lithography-free optical solar reflector metasurface for the radiative cooling of spacecraft
(SPIE, 2019)Optical Solar Reflectors (OSRs) form the physical interface between the spacecraft and space and they are essential for the stabilization and uniform distribution of temperature throughout the spacecraft. OSRs need to ... -
Effect of gate structures on the DC and RF performance of AlGaN/GaN HEMTs
(Institute of Physics Publishing, 2018)This work analyzes the effect of various gate structures on the DC and radio frequency (RF) performance of AlGaN/GaN high-electron mobility transistors (HEMTs). AlGaN/GaN HEMT devices with a 3 μm drain-to-source spacing, ... -
Saturation magnetization change with structure in CoFe2O4 nanostructures prepared from metallic iron and cobalt by wet grinding method
(Gazi Üniversitesi Mühendislik-Mimarlık, 2019)Nanocrystalline cobalt ferrite (CoFe2O4) has been synthesized directly from metallic cobalt (Co) and iron (Fe) via wet-milling followed by calcination. The calcination took place in atmosphere at 750 ◦C. After calcination, ... -
Selectively dry etched of p-GaN/InAlN heterostructures using BCI3-based plasma for normally-off HEMT technology
(Institute of Physics Publishing Ltd., 2021-12-10)In this paper, an alternative selective dry etching of p-GaN over InAlN was studied as a function of the ICP source powers, RF chuck powers and process pressures by using inductively coupled plasma reactive ion etching ... -
Spectrally selective ultrathin photodetectors using strong interference in nanocavity design
(Institute of Electrical and Electronics Engineers Inc., 2019)Thinning the active layer's thickness of the semiconductor down to a level comparable with the carriers' diffusion length while keeping its absorption high is an ultimate goal to boost the performance of optoelectronic ... -
Structural field plate length optimization for high power applications
(IEEE, 2014)In this work, we report GaN high-electron-mobility-transistors (HEMTs) on SiC with field plates of various dimensions for optimum performance. 0.6 μm gate length, 3 μm drain source space AlGaN/GaN HEMTs with field-plate ... -
A study on GaN-based betavoltaic batteries
(Institute of Physics Publishing Ltd., 2022-10-27)In this paper, a GaN-based betavoltaic epitaxial structure was grown by metal–organic chemical vapor deposition and a p-type ohmic contact was studied for different Ni/Au metal thickness ratios, temperature dependent in ... -
Visible light nearly perfect absorber: an optimum unit cell arrangement for near absolute polarization insensitivity
(OSA - The Optical Society, 2017)In this work, we propose an optimum unit cell arrangement to obtain near absolute polarization insensitivity in a metal-insulator-metal (MIM) based ultra-broadband perfect absorber. Our findings prove that upon utilizing ...
