Adsorbate-induced enhancement of the spectral response in graphene/silicon-based Schottky barrier photodetectors

The impact of atmospheric adsorbates on the spectral response and response speed of p-type graphene/n-type Silicon (p-Gr/n-Si) based Schottky barrier photodetectors are investigated. Wavelength resolved photocurrent and transient photocurrent spectroscopy measurements conducted under high-vacuum con...

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Bibliographic Details
Published in:Applied physics. A, Materials science & processing Materials science & processing, 2020-12, Vol.126 (12), Article 938
Main Authors: Şahan, N., Fidan, M., Çelebi, C.
Format: Article
Language:English
Subjects:
Adsorbates
Applied physics
Characterization and Evaluation of Materials
Condensed Matter Physics
Current carriers
Depletion
Fermi level
Graphene
Heterojunctions
Machines
Manufacturing
Materials science
Nanotechnology
Optical and Electronic Materials
Photoelectric effect
Photoelectric emission
Photometers
Physics
Physics and Astronomy
Processes
Silicon
Spectra
Spectral sensitivity
Surfaces and Interfaces
Thin Films
Two dimensional materials
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Summary:The impact of atmospheric adsorbates on the spectral response and response speed of p-type graphene/n-type Silicon (p-Gr/n-Si) based Schottky barrier photodetectors are investigated. Wavelength resolved photocurrent and transient photocurrent spectroscopy measurements conducted under high-vacuum conditions revealed that the atmospheric adsorbates such as O 2 and H 2 O stuck on graphene electrode lead to hole doping in graphene and therefore shift its Fermi level towards higher energy states below its Dirac point. Such a shift in graphene’s Fermi level due to adsorbates increases the zero-bias Schottky barrier height of the p-Gr/n-Si heterojunction from 0.71 to 0.78 eV. Adsorbate induced increment in the barrier height promotes the separation of photo-generated charge carriers at the depletion region and leads to an improvement in the maximum spectral response (e.g., from 0.39 to 0.46 AW −1 ) and response speed of the p-Gr/n-Si photodetector in the near-infrared region. The experimentally obtained results are expected to give an insight into the adsorbate related variations in the rectification and photo-response characters of the heterojunctions of graphene and other 2D materials with different semiconductors.
ISSN:0947-8396
1432-0630
DOI:10.1007/s00339-020-04120-1