Physics / Fizik

Permanent URI for this collectionhttps://hdl.handle.net/11147/6

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Institution Author: search.filters.institutionAuthor.Fidan, MehmetSubject: search.filters.subject.Graphene

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  • Article
    Citation - WoS: 4
    Citation - Scopus: 4
    Graphene/Soi-based Self-Powered Schottky Barrier Photodiode Array
    (American Institute of Physics, 2022) Yanılmaz, Alper; Fidan, Mehmet; Ünverdi, Özhan; Çelebi, Cem
    We have fabricated a four-element graphene/silicon on insulator (SOI) based Schottky barrier photodiode array (PDA) and investigated its optoelectronic device performance. In our device design, monolayer graphene is utilized as a common electrode on a lithographically defined linear array of n-type Si channels on a SOI substrate. As revealed by wavelength resolved photocurrent spectroscopy measurements, each element in the PDA structure exhibited a maximum spectral responsivity of around 0.1 A/W under a self-powered operational mode. Time-dependent photocurrent spectroscopy measurements showed excellent photocurrent reversibility of the device with ∼1.36 and ∼1.27 μs rise time and fall time, respectively. Each element in the array displayed an average specific detectivity of around 1.3 × 1012 Jones and a substantially small noise equivalent power of ∼0.14 pW/Hz-1/2. The study presented here is expected to offer exciting opportunities in terms of high value-added graphene/Si based PDA device applications such as multi-wavelength light measurement, level metering, high-speed photometry, and position/motion detection.
  • Article
    Citation - WoS: 12
    Citation - Scopus: 17
    Junction Area Dependent Performance of Graphene/Silicon Based Self-Powered Schottky Photodiodes
    (Elsevier, 2021) Fidan, Mehmet; Ünverdi, Özhan; Çelebi, Cem
    This work reports the impact of junction area on the device performance parameters of Graphene/n-Silicon (Gr/n-Si) based Schottky photodiodes. Herein, three batches of Gr/n-Si photodiode samples were produced based on various sized CVD grown monolayer graphene layers transferred on individual n-Si substrates. The fabricated devices exhibited strong Schottky diode character and had high spectral sensi-tivity at 905 nm peak wavelength. The optoelectronic measurements showed that the spectral response of Gr/n-Si Schottky photodiodes has a linear dependence on the active junction area. The sample with 20 mm(2) junction area reached a spectral response of 0.76 AW(-1), which is the highest value reported in the literature for self-powered Gr/n-Si Schottky photodiodes without the modification of graphene electrode. In contrast to their spectral responsivities, the response speed of the samples were found to be lowered as a function of the junction area. The experimental results demonstrated that the device performance of Gr/n-Si Schottky photodiodes can be modified simply by changing the size of the graphene electrode on n-Si without need of external doping of graphene layer or engineering Gr/n-Si interface. This study may serve towards the standardization of junction area for the development of high performance Gr/Si based optoelectronic devices such as solar cells and photodetectors operating in between the ultraviolet and near-infrared spectral region. (C) 2021 Elsevier B.V. All rights reserved.