Photoresponse of Graphene Channel in Graphene-Oxide–Silicon Photodetectors

Graphene-on-silicon photodetectors exhibit broadband detection capabilities with high responsivities, surpassing those of their counterpart semiconductors fabricated purely using graphene or Si. In these studies, graphene channels were considered electrically neutral, and signal amplification was ty...

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Main Authors: Kuo-Chih Lee, Yu-Hsien Chuang, Chen-Kai Huang, Hui Li, Guo-En Chang, Kuan-Ming Hung, Hung Hsiang Cheng
Format: Article
Language:English
Published: MDPI AG 2023-05-01
Series:Photonics
Subjects:
Online Access:https://www.mdpi.com/2304-6732/10/5/568
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author Kuo-Chih Lee
Yu-Hsien Chuang
Chen-Kai Huang
Hui Li
Guo-En Chang
Kuan-Ming Hung
Hung Hsiang Cheng
author_facet Kuo-Chih Lee
Yu-Hsien Chuang
Chen-Kai Huang
Hui Li
Guo-En Chang
Kuan-Ming Hung
Hung Hsiang Cheng
author_sort Kuo-Chih Lee
collection DOAJ
description Graphene-on-silicon photodetectors exhibit broadband detection capabilities with high responsivities, surpassing those of their counterpart semiconductors fabricated purely using graphene or Si. In these studies, graphene channels were considered electrically neutral, and signal amplification was typically attributed to the photogating effect. By contrast, herein, we show graphene channels to exhibit p-type characteristics using a structure wherein a thin oxide layer insulated the graphene from Si. The p-type carrier concentration is higher (six-times) than the photoaging-induced carrier concentration and dominates the photocurrent. Additionally, we demonstrate photocurrent tunability in the channel. By operating this device under a back-gated bias, photocurrent tuning is realized with not only amplification but also attenuation. Gate amplification produces a current equal to the photogating current at a low bias (0.2 V), and it is approximately two orders of magnitude larger at a bias of 2 V, indicating the operation effectiveness. Meanwhile, photocurrent attenuation enables adjustments in the detector output for compatibility with read-out circuits. A quantification model of gate-dependent currents is further established based on the simulation model used for metal–oxide–semiconductor devices. Thus, this study addresses fundamental issues concerning graphene channels and highlights the potential of such devices as gate-tunable photodetectors in high-performance optoelectronics.
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spelling doaj.art-bd24661721b94bdaadc3d8fa5f4628f22023-11-18T02:54:36ZengMDPI AGPhotonics2304-67322023-05-0110556810.3390/photonics10050568Photoresponse of Graphene Channel in Graphene-Oxide–Silicon PhotodetectorsKuo-Chih Lee0Yu-Hsien Chuang1Chen-Kai Huang2Hui Li3Guo-En Chang4Kuan-Ming Hung5Hung Hsiang Cheng6Center for Condensed Matter Sciences and Graduate Institute of Electronics Engineering, National Taiwan University, Taipei 106, TaiwanGraduate School of Advanced Technology Program for Semiconductor Devices, Materials, and Hetero-Integration, National Taiwan University, Taipei 106, TaiwanCenter for Condensed Matter Sciences and Graduate Institute of Electronics Engineering, National Taiwan University, Taipei 106, TaiwanCenter for Condensed Matter Sciences and Graduate Institute of Electronics Engineering, National Taiwan University, Taipei 106, TaiwanDepartment of Mechanical Engineering, and Advanced Institute of Manufacturing with High-Tech Innovations, National Chung Cheng University, Chiayi County 62102, TaiwanDepartment of Electronics Engineering, National Kaohsiung University of Science and Technology, Kaohsiung 807, TaiwanCenter for Condensed Matter Sciences and Graduate Institute of Electronics Engineering, National Taiwan University, Taipei 106, TaiwanGraphene-on-silicon photodetectors exhibit broadband detection capabilities with high responsivities, surpassing those of their counterpart semiconductors fabricated purely using graphene or Si. In these studies, graphene channels were considered electrically neutral, and signal amplification was typically attributed to the photogating effect. By contrast, herein, we show graphene channels to exhibit p-type characteristics using a structure wherein a thin oxide layer insulated the graphene from Si. The p-type carrier concentration is higher (six-times) than the photoaging-induced carrier concentration and dominates the photocurrent. Additionally, we demonstrate photocurrent tunability in the channel. By operating this device under a back-gated bias, photocurrent tuning is realized with not only amplification but also attenuation. Gate amplification produces a current equal to the photogating current at a low bias (0.2 V), and it is approximately two orders of magnitude larger at a bias of 2 V, indicating the operation effectiveness. Meanwhile, photocurrent attenuation enables adjustments in the detector output for compatibility with read-out circuits. A quantification model of gate-dependent currents is further established based on the simulation model used for metal–oxide–semiconductor devices. Thus, this study addresses fundamental issues concerning graphene channels and highlights the potential of such devices as gate-tunable photodetectors in high-performance optoelectronics.https://www.mdpi.com/2304-6732/10/5/568graphenephotodetectorphotogating
spellingShingle Kuo-Chih Lee
Yu-Hsien Chuang
Chen-Kai Huang
Hui Li
Guo-En Chang
Kuan-Ming Hung
Hung Hsiang Cheng
Photoresponse of Graphene Channel in Graphene-Oxide–Silicon Photodetectors
Photonics
graphene
photodetector
photogating
title Photoresponse of Graphene Channel in Graphene-Oxide–Silicon Photodetectors
title_full Photoresponse of Graphene Channel in Graphene-Oxide–Silicon Photodetectors
title_fullStr Photoresponse of Graphene Channel in Graphene-Oxide–Silicon Photodetectors
title_full_unstemmed Photoresponse of Graphene Channel in Graphene-Oxide–Silicon Photodetectors
title_short Photoresponse of Graphene Channel in Graphene-Oxide–Silicon Photodetectors
title_sort photoresponse of graphene channel in graphene oxide silicon photodetectors
topic graphene
photodetector
photogating
url https://www.mdpi.com/2304-6732/10/5/568
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