Yazar "Okyay, Ali Kemal" seçeneğine göre listele

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    Atomic layer deposition synthesized TiOx thin films and their application as microbolometer active materials
    (A V S Amer Inst Physics, 2016) Tanrikulu, Mahmud Yusuf; Rasouli, Hamid Reza; Ghaffari, Mohammad; Topalli, Kagan; Okyay, Ali Kemal
    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. It is found that the temperature coefficient of resistance values can be controlled by coating/annealing processes, and the value as high as -9%/K near room temperature is obtained. The noise properties of TiOx films are characterized. It is shown that TiOx films grown by atomic layer deposition technique could have a significant potential to be used as a new active material for microbolometer-based applications. (C) 2016 American Vacuum Society.
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    Atomic-layer-deposited zinc oxide as tunable uncooled infrared microbolometer material
    (Wiley-V C H Verlag Gmbh, 2014) Battal, Enes; Bolat, Sami; Tanrikulu, M. Yusuf; Okyay, Ali Kemal; Akin, Tayfun
    ZnO is an attractive material for both electrical and optical applications due to its wide bandgap of 3.37eV and tunable electrical properties. Here, we investigate the application potential of atomic-layer-deposited ZnO in uncooled microbolometers. The temperature coefficient of resistance is observed to be as high as -10.4%K-1 near room temperature with the ZnO thin film grown at 120 degrees C. Spectral noise characteristics of thin films grown at various temperatures are also investigated and show that the 120 degrees C grown ZnO has a corner frequency of 2kHz. With its high TCR value and low electrical noise, atomic-layer-deposited (ALD) ZnO at 120 degrees C is shown to possess a great potential to be used as the active layer of uncooled microbolometers. The optical properties of the ALD-grown ZnO films in the infrared region are demonstrated to be tunable with growth temperature from near transparent to a strong absorber. We also show that ALD-grown ZnO can outperform commercially standard absorber materials and appears promising as a new structural material for microbolometer-based applications.
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    Digitally alloyed ZnO and TiO2 thin film thermistors by atomic layer deposition for uncooled microbolometer applications
    (A V S Amer Inst Physics, 2017) Tilkioglu, Bilge T.; Bolat, Sami; Tanrikulu, Mahmud Yusuf; Okyay, Ali Kemal
    The authors demonstrate the digital alloying of ZnO and TiO2 via atomic layer deposition method to be utilized as the active material of uncooled microbolometers. Depositions are carried out at 200 degrees C. Crystallinity of the material is shown to be degraded with the increase of the Ti content in the grown film. A maximum temperature coefficient of resistance (TCR) of 5.96%/K is obtained with the films containing 12.2 at. % Ti, and the obtained TCR value is shown to be temperature insensitive in the 15-22 degrees C, thereby allowing a wide range of operation temperatures for the low cost microbolometers. (C) 2017 American Vacuum Society.
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    Öğe
    LWIR all-atomic layer deposition ZnO bilayer microbolometer for thermal imaging
    (Spie-Soc Photo-Optical Instrumentation Engineers, 2017) Poyraz, Muhammet; Gorgulu, Kazim; Sisman, Zulkarneyn; Tanrikulu, Mahmud Yusuf; Okyay, Ali Kemal
    We propose an all-ZnO bilayer microbolometer, operating in the long-wave infrared regime that can be implemented by consecutive atomic layer deposition growth steps. Bilayer design of the bolometer provides very high absorption coefficients compared to the same thickness of a single ZnO layer. High absorptivity of the bilayer structure enables higher performance (lower noise equivalent temperature difference and time constant values) compared to single-layer structure. We observe these results computationally by conducting both optical and thermal simulations. (C) 2017 Society of Photo-Optical Instrumentation Engineers (SPIE)