TY - JOUR
T1 - Broadband InSe/MoS2 Type-II Heterojunction Photodetector with Gate-Tunable Polarity Induced Near-Linear Wavelength-Dependent Photocurrent Peak
AU - Zhang, Wenying
AU - Chiao, Kuan Hao
AU - Huang, Hsin Wen
AU - Abid, Mohamed
AU - Ó Coileáin, Cormac
AU - Hung, Kuan Ming
AU - Chang, Ching Ray
AU - Wu, Yuh Renn
AU - Wu, Han Chun
N1 - Publisher Copyright:
© 2025 American Chemical Society.
PY - 2025/2/26
Y1 - 2025/2/26
N2 - Selectable polarity in van der Waals materials not only broadens the scope of design for electronic components but also opens new avenues for the development of advanced electronic, optoelectronic, and sensor devices. In this study, we fabricated vertically stacked InSe/MoS2 van der Waals type-II heterojunction photodetectors and conducted a systematic investigation of their photoelectrical properties. Our findings demonstrate the high performance of these photodetectors, characterized by effective suppression of charge recombination, the presence of both positive and negative photoconductivity under different incident light excitations, broad-spectrum detection ranging from 400 to 1064 nm, and remarkable responsivity and photodetectivity values of 10,200 A/W (−1430 A/W) and 3 × 1013 cm Hz-1/2 W-1 (3.6 × 1011 cm Hz-1/2 W-1) at 532 nm (1064 nm), respectively. Additionally, the fabricated photodetectors exhibit a gate-tunable polarity transition at a gate voltage of −20 V, leading to a photocurrent peak, the position of which shows a near-linear dependence on the incident light wavelength. By applying external gate voltages, the van der Waals heterojunctions can flexibly switch between functions such as photodetection, modulation, and storage in different applications, providing new scope for the design of integrated circuits and the development of multifunctional devices. Through Poisson and drift-diffusion simulations, we attribute the observed negative photoresponse to electrons excited from the InSe valence band to the MoS2 conduction band and subsequently trapped at the interface. The photocurrent peak arises from charge carrier accumulation at the interface, with its position determined by the interplay between the hole accumulation density in InSe and electron accumulation density in MoS2. Our results present a promising opportunity for the design of compact spectrometers based on van der Waals type-II heterojunction photodetectors.
AB - Selectable polarity in van der Waals materials not only broadens the scope of design for electronic components but also opens new avenues for the development of advanced electronic, optoelectronic, and sensor devices. In this study, we fabricated vertically stacked InSe/MoS2 van der Waals type-II heterojunction photodetectors and conducted a systematic investigation of their photoelectrical properties. Our findings demonstrate the high performance of these photodetectors, characterized by effective suppression of charge recombination, the presence of both positive and negative photoconductivity under different incident light excitations, broad-spectrum detection ranging from 400 to 1064 nm, and remarkable responsivity and photodetectivity values of 10,200 A/W (−1430 A/W) and 3 × 1013 cm Hz-1/2 W-1 (3.6 × 1011 cm Hz-1/2 W-1) at 532 nm (1064 nm), respectively. Additionally, the fabricated photodetectors exhibit a gate-tunable polarity transition at a gate voltage of −20 V, leading to a photocurrent peak, the position of which shows a near-linear dependence on the incident light wavelength. By applying external gate voltages, the van der Waals heterojunctions can flexibly switch between functions such as photodetection, modulation, and storage in different applications, providing new scope for the design of integrated circuits and the development of multifunctional devices. Through Poisson and drift-diffusion simulations, we attribute the observed negative photoresponse to electrons excited from the InSe valence band to the MoS2 conduction band and subsequently trapped at the interface. The photocurrent peak arises from charge carrier accumulation at the interface, with its position determined by the interplay between the hole accumulation density in InSe and electron accumulation density in MoS2. Our results present a promising opportunity for the design of compact spectrometers based on van der Waals type-II heterojunction photodetectors.
KW - broadband detection
KW - carrier accumulation
KW - InSe/MoS
KW - positive and negative photoconductivity
KW - tunable polarity
KW - type-II heterojunction
UR - https://www.scopus.com/pages/publications/85217903185
U2 - 10.1021/acsami.4c22132
DO - 10.1021/acsami.4c22132
M3 - Article
C2 - 39963896
AN - SCOPUS:85217903185
SN - 1944-8244
VL - 17
SP - 12941
EP - 12951
JO - ACS Applied Materials and Interfaces
JF - ACS Applied Materials and Interfaces
IS - 8
ER -