High-Performance Multifunctional Photodetector and THz Modulator Based on Graphene/TiO2/p-Si Heterojunction

In this paper, we have reported a multifunctional device from graphene/TiO 2 /p-Si heterojunction, followed by its systematical analysis of optical response in a device under ultraviolet–visible-infrared band and transmission changes of terahertz waves in the 0.3–1.0 THz band under different bias vo...

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Bibliographic Details
Published in:Nanoscale research letters 2021-08, Vol.16 (1), p.134-134, Article 134
Main Authors: Wei, Miaoqing, Zhang, Dainan, Zhang, Lei, Jin, Lichuan, Zhang, Huaiwu
Format: Article
Language:English
Subjects:
Bias
Broadband THz wave modulator
Chemistry and Materials Science
Depletion
Energy bands
Graphene
Graphene/TiO2/p-Si
Heterojunctions
Infrared analysis
Irradiation
Low Dimensional Electric and Photonic Materials and Devices
Materials Science
Modulation
Molecular Medicine
Multifunctional device
Nano Express
Nanochemistry
Nanoscale Science and Technology
Nanotechnology
Nanotechnology and Microengineering
Photodetector
Photometers
Semiconductor diodes
Silicon
Terahertz frequencies
Titanium dioxide
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Summary:In this paper, we have reported a multifunctional device from graphene/TiO 2 /p-Si heterojunction, followed by its systematical analysis of optical response in a device under ultraviolet–visible-infrared band and transmission changes of terahertz waves in the 0.3–1.0 THz band under different bias voltages. It is found that photodetector in the “back-to-back” p-n-p energy band structure has a seriously unbalanced distribution of photogenerated carriers in the vertical direction when light is irradiated from the graphene side. So this ensures a higher optical gain of the device in the form of up to 3.6 A/W responsivities and 4 × 10 13 Jones detectability under 750 nm laser irradiation. Besides, the addition of TiO 2 layer in this terahertz modulator continuously widens the carrier depletion region under negative bias, thereby realizing modulation of the terahertz wave, making the modulation depth up to 23% under − 15 V bias. However, almost no change is observed in the transmission of terahertz wave when a positive bias is applied. A similar of an electronic semiconductor diode is observed that only allows the passage of terahertz wave for negative bias and blocks the positive ones. Graphic Abstract
ISSN:1556-276X
1931-7573
1556-276X
DOI:10.1186/s11671-021-03589-w