Browsing by Author "celebi, Cem"

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    Enhancing the photo-response characteristics of graphene/n-Si based Schottky barrier photodiodes by increasing the number of graphene layers
    (AVS Science and Technology Society, 2022) Mehmet Fidan; Özhan Ünverdi; Cem Celebi; Fidan, Mehmet; celebi, Cem; uenverdi, Oezhan; Ünverdi, Özhan
    The impact of the number of graphene layers on the spectral responsivity and response speed of graphene/n-type Si (Gr/n-Si)-based Schottky barrier photodiodes is investigated. Gr/n-Si photodiode devices are fabricated by transferring chemical vapor deposition-grown graphene layers one by one on n-Si substrates reaching up to three graphene layers. The devices show a clear rectifying Schottky character and have a maximum responsivity at a peak wavelength of 905 nm. Wavelength-resolved and time-dependent photocurrent measurements demonstrated that both spectral responsivity and response speed are enhanced as the number of graphene layers is increased from 1 to 3 on n-Si substrates. For example the spectral responsivity and the response speed of the fabricated device were found to be improved by about 15% (e.g. from 0.65 to 0.75 AW-1) and 50% (e.g. 14 to 7 μs) respectively when three graphene layers are used as the hole-collecting cathode electrode. The experimentally obtained results showed that the device parameters such as spectral responsivity and response speed of Gr/n-Si Schottky barrier photodiodes can be boosted simply by increasing the number of graphene layers on n-Si substrates. © 2022 Elsevier B.V. All rights reserved.