WoS İndeksli Yayınlar Koleksiyonu / WoS Indexed Publications Collection

Permanent URI for this collectionhttps://hdl.handle.net/11147/7150

Browse

Filters

2025 - 20262

Settings

Department: search.filters.department.İzmir Institute of TechnologySubject: search.filters.subject.Graphene

Search Results

Now showing 1 - 2 of 2
  • Article
    Comparison of the Photoresponse Characteristics for 4H-SiC Schottky Barrier UV Photodetector with Graphene and Ni/Cr Electrode
    (Elsevier, 2026) Çelebi, Cem; Gozek, Melike; Unverdi, Ozhan; Celebi, Cem; 04.05. Department of Pyhsics; 04. Faculty of Science; 01. Izmir Institute of Technology
    Gr/4H-SiC and Ni/Cr/4H-SiC Schottky junction UV photodetectors were fabricated and investigated to reveal the effect of electrode materials on the device performance such as spectral response and response speed. I-V characterization, spectral response, and response speed (on-off) measurements were conducted for the UV wavelength range between 200 and 400 nm. The maximum photo-responsivity was obtained as 0.081 A/W for Gr/4H-SiC and 0.041 A/W for Ni/Cr/4H-SiC at a wavelength of 260 nm. This result was attributed to the higher optical transmittance of the graphene electrode compared to the semitransparent Ni/Cr electrode. Zero bias response speed measurements were done under 280 nm wavelength UV light pulsed at different frequencies such as 100 Hz, 500 Hz, and 1000 Hz. The Gr/4H-SiC and Ni/Cr/4H-SiC photodetectors show distinctly different decay times of 5.04 ms and 305.1 mu s, respectively, while their rise times were found to be similar. This observation has been explained by the inclination of graphene to act as a trap site for photogenerated holes.
  • Article
    Passive Matrix Schottky Barrier 2d Photodiode Array on Graphene/Soi Platform
    (Springer Science and Business Media Deutschland GmbH, 2025) Çelebi, Cem; Ünverdi, Ö.; Çelebi, C.; 04.05. Department of Pyhsics; 04. Faculty of Science; 01. Izmir Institute of Technology
    We fabricated 4 × 4 pixel two-dimensional (2D) photodiode array (PDA) out of monolayer graphene and n-type silicon (n-Si) electrodes on a silicon-on-insulator (SOI) substrate. Our device design is based on passive matrix sensor array architecture consisting of individual graphene and silicon electrodes aligned perpendicular to each other. I-V measurements conducted at room temperature to reveal the electronic characteristics of graphene and Si junction in the device structure. The spectral responsivity, respond speed and the optical crosstalk of each G/Si pixels in the array have been determined by wavelength resolved and time dependent photocurrent spectroscopy measurements. Micro-Raman mapping measurements were conducted to examine the surface coverage of graphene electrode on each pixel. The results of Micro-Raman mapping measurements were correlated with the corresponding photocurrent data acquired under light illumination. We believe that this work constitutes a significant potential in integrating variety of 2D materials and SOI technology into next generation image sensing and multiple pixel light detection applications. © The Author(s) 2025.