Dr. Ali Kemal Okyay Profile

Dr. Ali Kemal Okyay

Prof at Bilkent Univ

SPIE Involvement:

Author

Publications (13)

Proceedings Article | 29 May 2018 Presentation + Paper

Single layer microbolometer detector pixel using ZnO material

M. Yusuf Tanrikulu, Ciğdem Yildizak, Ali Okyay, Orhan Akar, Adem Sarac, Tayfun Akin

Proceedings Volume 10624, 1062417 (2018) https://doi.org/10.1117/12.2302996

KEYWORDS: Microbolometers, Sensors, Zinc oxide, Atomic layer deposition, Resistance, Device simulation, Defense and security

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SPIE Journal Paper | 15 March 2017

LWIR all-atomic layer deposition ZnO bilayer microbolometer for thermal imaging

Muhammet Poyraz, Kazim Gorgulu, Zulkarneyn Sisman, Mahmud Yusuf Tanrikulu, Ali Okyay

OE, Vol. 56, Issue 03, 037106, (March 2017) https://doi.org/10.1117/12.10.1117/1.OE.56.3.037106

KEYWORDS: Zinc oxide, Microbolometers, Sensors, Absorption, Thermography, Long wavelength infrared, Atomic layer deposition, Bolometers, Optical simulations, Infrared imaging

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Proceedings Article | 23 February 2017 Paper

MIMIM photodetectors using plasmonically enhanced MIM absorbers

S. Abedini Dereshgi, A. Okyay

Proceedings Volume 10099, 100991C (2017) https://doi.org/10.1117/12.2253026

KEYWORDS: Metals, Silver, Photodetectors, Plasmonics, Chromium, Dewetting, Nanoparticles, Gold, Absorption, Aluminum

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Proceedings Article | 5 October 2015 Presentation

Template-assisted synthesis of III-nitride and metal-oxide nano-heterostructures using low-temperature atomic layer deposition for energy, sensing, and catalysis applications (Presentation Recording)

Necmi Biyikli, Cagla Ozgit-Akgun, Hamit Eren, Ali Haider, Tamer Uyar, Fatma Kayaci, Mustafa Ozgur Guler, Ruslan Garifullin, Ali Okyay, Gamze Ulusoy, Eda Goldenberg

Proceedings Volume 9553, 95530C (2015) https://doi.org/10.1117/12.2190261

KEYWORDS: Atomic layer deposition, Catalysis, Nanolithography, Nanostructures, Dye sensitized solar cells, Solar energy, Alternate lighting of surfaces, Nanostructuring, Polymers, Nanofibers

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Recent experimental research efforts on developing functional nanostructured III-nitride and metal-oxide materials via low-temperature atomic layer deposition (ALD) will be reviewed. Ultimate conformality, a unique propoerty of ALD process, is utilized to fabricate core-shell and hollow tubular nanostructures on various nano-templates including electrospun nanofibrous polymers, self-assembled peptide nanofibers, metallic nanowires, and multi-wall carbon nanotubes (MWCNTs). III-nitride and metal-oxide coatings were deposited on these nano-templates via thermal and plasma-enhanced ALD processes with thickness values ranging from a few mono-layers to 40 nm. Metal-oxide materials studied include ZnO, TiO2, HfO2, ZrO2, and Al2O3. Standard ALD growth recipes were modified so that precursor molecules have enough time to diffuse and penetrate within the layers/pores of the nano-template material. As a result, uniform and conformal coatings on high-surface area nano-templates were demonstrated. Substrate temperatures were kept below 200C and within the self-limiting ALD window, so that temperature-sensitive template materials preserved their integrity III-nitride coatings were applied to similar nano-templates via plasma-enhanced ALD (PEALD) technique. AlN, GaN, and InN thin-film coating recipes were optimized to achieve self-limiting growth with deposition temperatures as low as 100C. BN growth took place only for >350C, in which precursor decomposition occured and therefore growth proceeded in CVD regime. III-nitride core-shell and hollow tubular single and multi-layered nanostructures were fabricated. The resulting metal-oxide and III-nitride core-shell and hollow nano-tubular structures were used for photocatalysis, dye sensitized solar cell (DSSC), energy storage and chemical sensing applications. Significantly enhanced catalysis, solar efficiency, charge capacity and sensitivity performance are reported. Moreover, core-shell metal-oxide and III-nitride materials showed promise to be used in applications where flexibility is critical like functional membranes, textile and flexible electronic applications.

SPIE Journal Paper | 26 June 2015

Enhanced performance of dye-sensitized solar cells by omnidirectional antireflective coatings

Turkan Gamze Ulusoy, Bihter Daglar, Adem Yildirim, Amir Ghobadi, Mehmet Bayindir, Ali Okyay

JPE, Vol. 5, Issue 01, 053090, (June 2015) https://doi.org/10.1117/12.10.1117/1.JPE.5.053090

KEYWORDS: Coating, Dye sensitized solar cells, Antireflective coatings, Solar cells, Glasses, Silica, Reflection, Refractive index, Quantum efficiency, Scanning electron microscopy

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Proceedings Article | 27 February 2015 Paper

Ultra-low-cost near-infrared photodetectors on silicon

M. Nazirzadeh, Fatih Atar, B. Berkan Turgut, Ali Okyay

Proceedings Volume 9367, 93671I (2015) https://doi.org/10.1117/12.2078913

KEYWORDS: Silicon, Gold, Metals, Near infrared, Annealing, Electrons, Photodetectors, Semiconducting wafers, Neodymium, Nanoantennas

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SPIE Journal Paper | 9 October 2014

Metal-semiconductor-metal ultraviolet photodetectors based on gallium nitride grown by atomic layer deposition at low temperatures

Burak Tekcan, Cagla Ozgit-Akgun, Sami Bolat, Necmi Biyikli, Ali Okyay

OE, Vol. 53, Issue 10, 107106, (October 2014) https://doi.org/10.1117/12.10.1117/1.OE.53.10.107106

KEYWORDS: Gallium nitride, Ultraviolet radiation, Photodetectors, Atomic layer deposition, Palladium, Nanotechnology, Nitrogen, Optoelectronics, Semiconductors, Thin films

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Proceedings Article | 24 June 2014 Paper

Broadband absorption enhancement in an uncooled microbolometer infrared detector

Basak Kebapci, Ozgecan Dervisoglu, Enes Battal, Ali Kemal Okyay, Tayfun Akin

Proceedings Volume 9070, 907021 (2014) https://doi.org/10.1117/12.2069937

KEYWORDS: Plasmonics, Absorption, Microbolometers, Electrodes, Metals, Polarization, Image processing, Scanning electron microscopy, Infrared detectors, Long wavelength infrared

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Proceedings Article | 11 June 2013 Paper

A plasmonically enhanced pixel structure for uncooled microbolometer detectors

Ozan Erturk, Enes Battal, Seniz Esra Kucuk, Ali Kemal Okyay, Tayfun Akin

Proceedings Volume 8704, 87041E (2013) https://doi.org/10.1117/12.2019540

KEYWORDS: Microbolometers, Absorption, Plasmonics, Silicon, Infrared radiation, Long wavelength infrared, Infrared imaging, Scanning electron microscopy, Imaging systems, Sensors

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Proceedings Article | 18 March 2013 Paper

ZnO based optical modulator in the visible wavelengths

Ali Okyay, Levent Aygün, Feyza Oruç

Proceedings Volume 8626, 86261T (2013) https://doi.org/10.1117/12.2005558

KEYWORDS: Zinc oxide, Absorption, Optical modulators, Visible radiation, Thin films, Atomic layer deposition, Transistors, Optical design, Active optics, Oxides

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Proceedings Article | 18 March 2013 Paper

TiO2 thin film transistor by atomic layer deposition

Ali Okyay, Feyza Oruç, Furkan Çimen, Levent Aygün

Proceedings Volume 8626, 862616 (2013) https://doi.org/10.1117/12.2005528

KEYWORDS: Atomic layer deposition, Thin films, Transistors, Measurement devices, Annealing, Ultraviolet radiation, Absorption, Thin film deposition, Dielectrics, Titanium dioxide

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Proceedings Article | 31 May 2012 Paper

An analysis for the broad-band absorption enhancement using plasmonic structures on uncooled infrared detector pixels

Sevil Lulec, Seniz Kucuk, Enes Battal, Ali Okyay, M. Yusuf Tanrikulu, Tayfun Akin

Proceedings Volume 8353, 83531D (2012) https://doi.org/10.1117/12.964549

KEYWORDS: Plasmonics, Absorption, Microbolometers, Metals, Silicon, Finite-difference time-domain method, Gold, Infrared radiation, Infrared detectors, Structural design

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Proceedings Article | 11 September 2010 Paper

Nanoantenna couplers for metal-insulator-metal waveguide interconnects

M. Cengiz Onbasli, Ali Okyay

Proceedings Volume 7757, 77573R (2010) https://doi.org/10.1117/12.876177

KEYWORDS: Antennas, Waveguides, Plasmonics, Signal attenuation, Metals, Cladding, Near field, Copper, Silver, Nanoantennas

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Showing 5 of 13 publications

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