Browsing by Author "Okyay, Ali Kemal"
Now showing items 1-20 of 140
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2-nm laser-synthesized Si nanoparticles for low-power charge trapping memory devices
El-Atab, N.; Özcan, Ayşe; Alkış, Sabri; Okyay, Ali Kemal; Nayfeh, A. (IEEE, 2014-08)In this work, the effect of embedding Silicon Nanoparticles (Si-NPs) in ZnO based charge trapping memory devices is studied. Si-NPs are fabricated by laser ablation of a silicon wafer in deionized water followed by sonication ... -
∼3-nm ZnO nanoislands deposition and application in charge trapping memory grown by single ALD step
El-Atab, N.; Chowdhury F.; Ulusoy, T. G.; Ghobadi, A.; Nazirzadeh A.; Okyay, Ali Kemal; Nayfeh, A. (Nature Publishing Group, 2016)Low-dimensional semiconductor nanostructures are of great interest in high performance electronic and photonic devices. ZnO is considered to be a multifunctional material due to its unique properties with potential in ... -
Actively tunable thin films for visible light by thermo-optic modulation of ZnO
Battal, E.; Okyay, Ali Kemal (Wiley-VCH Verlag, 2016)Applications of active control of light matter interactions within integrated photonics, hyper-spectral imaging, reconfigurable lasers, and selective bio-surfaces have enormously increased the demand for realization of ... -
All-silicon ultra-broadband infrared light absorbers
Gorgulu, K.; Gok, A.; Yilmaz, M.; Topalli, K.; Blylkll, N.; Okyay, Ali Kemal (Nature Publishing Group, 2016)Absorbing infrared radiation efficiently is important for critical applications such as thermal imaging and infrared spectroscopy. Common infrared absorbing materials are not standard in Si VLSI technology. We demonstrate ... -
An all-ZnO microbolometer for infrared imaging
Kesim, Y. E.; Battal, E.; Tanrikulu, M. Y.; Okyay, Ali Kemal (Elsevier BV, 2014)Microbolometers are extensively used for uncooled infrared imaging applications. These imaging units generally employ vanadium oxide or amorphous silicon as the active layer and silicon nitride as the absorber layer. ... -
Amyloid-like peptide nanofiber templated titania nanostructures as dye sensitized solar cell anodic materials
Acar, H.; Garifullin, R.; Aygun, L. E.; Okyay, Ali Kemal; Güler, Mustafa O. (Royal Society of Chemistry, 2013)One-dimensional titania nanostructures can serve as a support for light absorbing molecules and result in an improvement in the short circuit current (Jsc) and open circuit voltage (Voc) as a nanostructured and high-surface-area ... -
An analysis for the broad-band absorption enhancement using plasmonic structures on uncooled infrared detector pixels
Lüleç, S. Z.; Küçük, S. E.; Battal, Enes; Okyay, Ali Kemal; Tanrıkulu, M. Y.; Akın, T. (SPIE, 2012-05)This paper introduces an analysis on the absorption enhancement in uncooled infrared pixels using resonant plasmon modes in metal structures, and it reports, for the first time in literature, broad-band absorption enhancement ... -
Atomic layer deposited HfO2 based metal insulator semiconductor GaN ultraviolet photodetectors
Kumar, M.; Tekcan, B.; Okyay, Ali Kemal (Elsevier BV, 2014)A report on GaN based metal insulator semiconductor (MIS) ultraviolet (UV) photodetectors (PDs) with atomic layer deposited (ALD) 5-nm-thick HfO2 insulating layer is presented. Very low dark current of 2.24 × 10-11 A and ... -
Atomic Layer Deposition for Vertically Integrated ZnO Thin Film Transistors: Toward 3D High Packing Density Thin Film Electronics
Sisman, Z.; Bolat, S.; Okyay, Ali Kemal (Wiley-VCH Verlag, 2017)We report on the first demonstration of the atomic layer deposition (ALD) based three dimensional (3D) integrated ZnO thin film transistors (TFTs) on rigid substrates. Devices exhibit high on-off ratio (∼106) and high ... -
Atomic layer deposition synthesized TiOx thin films and their application as microbolometer active materials
Tanrikulu, M. Y.; Rasouli, H. R.; Ghaffari, M.; Topalli K.; Okyay, Ali Kemal (AVS Science and Technology Society, 2016)This paper demonstrates the possible usage of TiOx thin films synthesized by atomic layer deposition as a microbolometer active material. Thin film electrical resistance is investigated as a function of thermal annealing. ... -
Atomic-layer-deposited zinc oxide as tunable uncooled infrared microbolometer material
Battal, E.; Bolat, S.; Tanrikulu, M. Y.; Okyay, Ali Kemal; Akin, T. (Wiley-VCH Verlag, 2014)ZnO is an attractive material for both electrical and optical applications due to its wide bandgap of 3.37 eV and tunable electrical properties. Here, we investigate the application potential of atomic-layer-deposited ZnO ... -
Au/TiO2 nanorod-based Schottky-type UV photodetectors
Karaagac, H.; Aygun, L. E.; Parlak, M.; Ghaffari, M.; Bıyıklı, Necmi; Okyay, Ali Kemal (Wiley, 2012-10-12)TiO2 nanorods (NRs) were synthesized on fluorine-doped tin oxide (FTO) pre-coated glass substrates using hydrothermal growth technique. Scanning electron microscopy studies have revealed the formation of vertically-aligned ... -
A baseball-bat-like CdTe/TiO2 nanorods-based heterojunction core–shell solar cell
Karaagac, H.; Parlak, M.; Aygun, L. E.; Ghaffari, M.; Bıyıklı, Necmi; Okyay, Ali Kemal (Elsevier, 2013)Rutile TiO2 nanorods on fluorine-doped thin oxide glass substrates via the hydrothermal technique were synthesized and decorated with a sputtered CdTe layer to fabricate a core-shell type n-TiO2/p-CdTe solar cell. Absorbance ... -
Broadband absorption enhancement in an uncooled microbolometer infrared detector
Kebapcı, B.; Dervişoğlu, Ö.; Battal, Enes; Okyay, Ali Kemal; Akın, T. (SPIE, 2014)This paper introduces a method for a broadband absorption enhancement in the LWIR range (8-12 μm), in single layer microbolometer pixels with 35 μm pitch. For the first time in the literature, this study introduces a very ... -
Broadband one way propagation via dielectric waveguides with unequal effective index
Öner, B. B.; Üstün, K.; Kurt, H.; Okyay, Ali Kemal; Turhan-Sayan, G. (IEEE, 2014)We present an efficient approach for broad band one way propagation of light by parallel and unequal dielectric waveguides leading different effective phase shifts. Three dimensional numerical simulations show that 30% ... -
Catalytic properties of vanadium diselenide: a comprehensive study on ıts electrocatalytic performance in alkaline, neutral, and acidic media
Ghobadi, T. G. U.; Patil, B.; Karadas, F.; Okyay, Ali Kemal; Yilmaz, E. (American Chemical Society, 2017)Here, we report the synthesis of vanadium diselenide (VSe2) three-dimensional nanoparticles (NPs) and two-dimensional (2D) nanosheets (NSs) utilizing nanosecond pulsed laser ablation technique followed by liquid-phase ... -
Charge Trapping Memory with 2.85-nm Si-Nanoparticles Embedded in HfO2
El-Atab, N.; Turgut, Berk Berkan; Okyay, Ali Kemal; Nayfeh, A. (ECS, 2015-05)In this work, the effect of embedding 2.85-nm Si-nanoparticles charge trapping layer in between double layers of high-κ Al<inf>2</inf>O<inf>3</inf>/HfO<inf>2</inf> oxides is studied. Using high frequency (1 MHz) ... -
Comparative study of thin film n-i-p a-Si: H solar cells to investigate the effect of absorber layer thickness on the plasmonic enhancement using gold nanoparticles
Islam, K.; Chowdhury F.I.; Okyay, Ali Kemal; Nayfeh, A. (Elsevier Ltd, 2015)In this paper, the effect of gold nanoparticles on n-i-p a-Si:H solar cells with different intrinsic layer (i-layer) thicknesses has been studied. 100nm and 500nm i-layer based n-i-p a-Si:H solar cells were fabricated and ... -
Complementary spiral resonators for ultrawideband suppression of simultaneous switching noise in high-speed circuits
Ghobadi, A.; Topalli K.; Bıyıklı, Necmi; Okyay, Ali Kemal (Electromagnetics Academy, 2014)In this paper, a novel concept for ultra-wideband simultaneous switching noise (SSN) mitigation in high-speed printed circuit boards (PCBs) is proposed. Using complementary spiral resonators (CSRs) etched on only a single ... -
Compositional homogeneity in a medical-grade stainless steel sintered with a Mn-Si additive
Salahinejad, E.; Hadianfard, M.J.; Ghaffari, M.; Mashhadi, S.B.; Okyay, Ali Kemal (Elsevier, 2012-06-09)In this paper, chemical composition uniformity in amorphous/ nanocrystallization medical-grade stainless steel (ASTM ID: F2581) sintered with a Mn-Si additive was studied via scanning electron microscopy, energy dispersive ...