Revealing the Active Role of the Gate Electrode in Weak-Light Detection

Tzu En Huang; Chen Yu Wang; Hua Hsing Liu; Bor Wei Liang; Shih Chia Peng; You Jia Huang; Yann Wen Lan; Kuan Ming Hung; Kuang Yao Lo

doi:10.1021/acsnano.5c13029

Revealing the Active Role of the Gate Electrode in Weak-Light Detection

Tzu En Huang
, Chen Yu Wang
, Hua Hsing Liu
, Bor Wei Liang
, Shih Chia Peng
, You Jia Huang
, Yann Wen Lan^*
, Kuan Ming Hung^*
, Kuang Yao Lo^*

^*Corresponding author for this work

Department of Physics

Research output: Contribution to journal › Article › peer-review

1 Citation (Scopus)

Abstract

The contribution of gate materials to the photoresponse of thin-film field-effect photodetectors has long been overlooked, with prior studies focusing primarily on photoconductive and photogating effects within the sensing layer. Here, we show that under weak illumination, photocarriers primarily originate from the silicon gate rather than the MoS₂ channel. Absorption spectra confirm that light is mainly absorbed by the gate, driving a negative photocurrent (NPC). The NPC magnitude and slope vary with illumination intensity and V_DS, suggesting transport dominated by Si/SiO₂ interface traps. NPC persists when MoS₂ is replaced with Au/Ti, reinforcing the gate-driven mechanism. At higher powers, band bending reverses due to competing photovoltaic and trap-induced potentials. These results highlight the active role of the gate and offer strategies for device optimization.

Original language	English
Pages (from-to)	8266-8274
Number of pages	9
Journal	ACS Nano
Volume	20
Issue number	10
DOIs	https://doi.org/10.1021/acsnano.5c13029
Publication status	Published - 2026 Mar 17

UN SDGs

This output contributes to the following UN Sustainable Development Goals (SDGs)

SDG 7 Affordable and Clean Energy

Keywords

MoSFET
gate-induced injection
interface traps
negative photocurrent
substrate-mediated effects
weak-light photodetection

ASJC Scopus subject areas

General Materials Science
General Engineering
General Physics and Astronomy

Access to Document

10.1021/acsnano.5c13029

Cite this

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title = "Revealing the Active Role of the Gate Electrode in Weak-Light Detection",

abstract = "The contribution of gate materials to the photoresponse of thin-film field-effect photodetectors has long been overlooked, with prior studies focusing primarily on photoconductive and photogating effects within the sensing layer. Here, we show that under weak illumination, photocarriers primarily originate from the silicon gate rather than the MoS2 channel. Absorption spectra confirm that light is mainly absorbed by the gate, driving a negative photocurrent (NPC). The NPC magnitude and slope vary with illumination intensity and VDS, suggesting transport dominated by Si/SiO2 interface traps. NPC persists when MoS2 is replaced with Au/Ti, reinforcing the gate-driven mechanism. At higher powers, band bending reverses due to competing photovoltaic and trap-induced potentials. These results highlight the active role of the gate and offer strategies for device optimization.",

keywords = "MoSFET, gate-induced injection, interface traps, negative photocurrent, substrate-mediated effects, weak-light photodetection",

author = "Huang, \{Tzu En\} and Wang, \{Chen Yu\} and Liu, \{Hua Hsing\} and Liang, \{Bor Wei\} and Peng, \{Shih Chia\} and Huang, \{You Jia\} and Lan, \{Yann Wen\} and Hung, \{Kuan Ming\} and Lo, \{Kuang Yao\}",

note = "Publisher Copyright: {\textcopyright} 2026 The Authors. Published by American Chemical Society",

year = "2026",

month = mar,

day = "17",

doi = "10.1021/acsnano.5c13029",

language = "English",

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T1 - Revealing the Active Role of the Gate Electrode in Weak-Light Detection

AU - Huang, Tzu En

AU - Wang, Chen Yu

AU - Liu, Hua Hsing

AU - Liang, Bor Wei

AU - Peng, Shih Chia

AU - Huang, You Jia

AU - Lan, Yann Wen

AU - Hung, Kuan Ming

AU - Lo, Kuang Yao

PY - 2026/3/17

Y1 - 2026/3/17

N2 - The contribution of gate materials to the photoresponse of thin-film field-effect photodetectors has long been overlooked, with prior studies focusing primarily on photoconductive and photogating effects within the sensing layer. Here, we show that under weak illumination, photocarriers primarily originate from the silicon gate rather than the MoS2 channel. Absorption spectra confirm that light is mainly absorbed by the gate, driving a negative photocurrent (NPC). The NPC magnitude and slope vary with illumination intensity and VDS, suggesting transport dominated by Si/SiO2 interface traps. NPC persists when MoS2 is replaced with Au/Ti, reinforcing the gate-driven mechanism. At higher powers, band bending reverses due to competing photovoltaic and trap-induced potentials. These results highlight the active role of the gate and offer strategies for device optimization.

AB - The contribution of gate materials to the photoresponse of thin-film field-effect photodetectors has long been overlooked, with prior studies focusing primarily on photoconductive and photogating effects within the sensing layer. Here, we show that under weak illumination, photocarriers primarily originate from the silicon gate rather than the MoS2 channel. Absorption spectra confirm that light is mainly absorbed by the gate, driving a negative photocurrent (NPC). The NPC magnitude and slope vary with illumination intensity and VDS, suggesting transport dominated by Si/SiO2 interface traps. NPC persists when MoS2 is replaced with Au/Ti, reinforcing the gate-driven mechanism. At higher powers, band bending reverses due to competing photovoltaic and trap-induced potentials. These results highlight the active role of the gate and offer strategies for device optimization.

KW - MoSFET

KW - gate-induced injection

KW - interface traps

KW - negative photocurrent

KW - substrate-mediated effects

KW - weak-light photodetection

UR - https://www.scopus.com/pages/publications/105032999950

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U2 - 10.1021/acsnano.5c13029

DO - 10.1021/acsnano.5c13029

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AN - SCOPUS:105032999950

SN - 1936-0851

VL - 20

SP - 8266

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JO - ACS Nano

JF - ACS Nano

IS - 10

ER -

Revealing the Active Role of the Gate Electrode in Weak-Light Detection

Abstract

UN SDGs

Keywords

ASJC Scopus subject areas

Access to Document

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