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Ultrasensitive Room-Temperature NO2 Gas Sensor Based on In2O3-NbS2 Heterojunction
Authors:
P K Shihabudeen,
Alex Sam,
Shih-Wen Chiu,
Ta-Jen Yen,
Kea-Tiong Tang
Abstract:
Niobium disulfide (NbS2), a two-dimensional transition metal dichalcogenide with semi metallic conductivity and high surface activity, offers promising properties for electronic and sensing applications. In this study, we report a high-performance NO2 gas sensor based on a heterostructure comprising a spin-coated In2O3 film on a semi-metallic NbS2 film.
Niobium disulfide (NbS2), a two-dimensional transition metal dichalcogenide with semi metallic conductivity and high surface activity, offers promising properties for electronic and sensing applications. In this study, we report a high-performance NO2 gas sensor based on a heterostructure comprising a spin-coated In2O3 film on a semi-metallic NbS2 film.
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Submitted 15 July, 2025;
originally announced July 2025.
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Highly Entangled Magnetodielectric and Magnetostriction effects, and Spin-Phonon coupling in the Antiferromagnetic Ni$_2$ScSbO$_6$
Authors:
Neha Patel,
Arkadeb Pal,
C. W. Wang,
G. R. Blake,
J. Khatua,
T. W. Yen,
Susaiammal Arokiasamy,
H. S. Kunwar,
Y. C. Lai,
Y. C. Chuang,
V. Sathe,
Kwang-Yong Choi,
H. D. Yang,
Sandip Chatterjee
Abstract:
Magnetic systems with noncentrosymmetric crystal structures are renowned for their complex magnetic ordering and diverse and fascinating physical properties. In this report, we provide a comprehensive study of the chiral magnetic system Ni$_2$ScSbO$_6$, which exhibits a robust incommensurate long-range antiferromagnetic spin ordering at a temperature of $T_N = 62$~K, as revealed by bulk magnetizat…
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Magnetic systems with noncentrosymmetric crystal structures are renowned for their complex magnetic ordering and diverse and fascinating physical properties. In this report, we provide a comprehensive study of the chiral magnetic system Ni$_2$ScSbO$_6$, which exhibits a robust incommensurate long-range antiferromagnetic spin ordering at a temperature of $T_N = 62$~K, as revealed by bulk magnetization, specific heat, and neutron diffraction studies. This magnetic ordering triggers a series of intriguing phenomena, including prominent magnetodielectric coupling manifested by a dielectric peak at $T_N$, significant spin-phonon coupling resulting in strong phonon renormalization characterized by anomalous softening of various Raman modes, and a remarkable volume magnetostriction effect probed by high-resolution synchrotron X-ray diffraction. These phenomena are intricately interlinked, positioning the present system as a rare and interesting material.
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Submitted 26 June, 2025; v1 submitted 7 March, 2025;
originally announced March 2025.
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Ultrahigh Photoresponsivity of Gold Nanodisk Array/CVD MoS$_2$-based Hybrid Phototransistor
Authors:
Shyam Narayan Singh Yadav,
Po-Liang Chen,
Yu-Chi Yao,
Yen-Yu Wang,
Der-Hsien Lien,
Yu-Jung Lu,
Ya-Ping Hsieh,
Chang-Hua Liu,
Ta-Jen Yen
Abstract:
Owing to its atomically thin thickness, layer-dependent tunable band gap, flexibility, and CMOS compatibility, MoS$_2$ is a promising candidate for photodetection. However, mono-layer MoS2-based photodetectors typically show poor optoelectronic performances, mainly limited by their low optical absorption. In this work, we hybridized CVD-grown monolayer MoS$_2$ with a gold nanodisk (AuND) array to…
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Owing to its atomically thin thickness, layer-dependent tunable band gap, flexibility, and CMOS compatibility, MoS$_2$ is a promising candidate for photodetection. However, mono-layer MoS2-based photodetectors typically show poor optoelectronic performances, mainly limited by their low optical absorption. In this work, we hybridized CVD-grown monolayer MoS$_2$ with a gold nanodisk (AuND) array to demonstrate a superior visible photodetector through a synergetic effect. It is evident from our experimental results that there is a strong light-matter interaction between AuNDs and monolayer MoS$_2$, which results in better photodetection due to a surface trap state passivation with a longer charge carrier lifetime compared to pristine MoS$_2$. In particular, the AuND/MoS$_2$ system demonstrated a photoresponsivity of $8.7 \times 10^{4}$ A/W, specific detectivity of $6.9 \times 10^{13}$ Jones, and gain $1.7 \times 10^{5}$ at $31.84 μW/cm^{2}$ illumination power density of 632 nm wavelength with an applied voltage of 4.0 V for an AuND/MoS$_2$-based photodetector. To our knowledge, these optoelectronic responses are one order higher than reported results for CVD MoS$_2$-based photodetector in the literature.
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Submitted 28 August, 2023;
originally announced August 2023.
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Superior visible photoelectric response with Au/Cu2NiSnS4 core-shell nanocrystals
Authors:
Anima Ghosh,
Shyam Narayan Singh Yadav,
Ming-Hsiu Tsai,
Abhishek Dubey,
Shangjr Gwo,
Chih-Ting Lin,
Ta- Jen Yen
Abstract:
The incorporation of plasmonic metal nanostructures into semiconducting chalcogenides, in the form of core-shell structures, represents a promising approach to boosting the performance of photodetectors. In this study, we combined Au nanoparticles with newly developed copper-based chalcogenides Cu2NiSnS4 (Au/CNTS), to achieve an ultrahigh optoelectronic response in the visible regime. The high-qua…
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The incorporation of plasmonic metal nanostructures into semiconducting chalcogenides, in the form of core-shell structures, represents a promising approach to boosting the performance of photodetectors. In this study, we combined Au nanoparticles with newly developed copper-based chalcogenides Cu2NiSnS4 (Au/CNTS), to achieve an ultrahigh optoelectronic response in the visible regime. The high-quality Au/CNTS core-shell structure was synthesized by developing a unique colloidal hot-injection method, which allowed excellent control over sizes, shapes, and elemental compositions. The fabricated Au/CNTS hybrid core-shell structure exhibited enhanced optical absorption, carrier extraction efficiency, and improved photo-sensing performance, owing to the plasmonic-induced resonance energy transfer effect of the Au core. This effect led to a significant increase in carrier density between the Au core and CNTS shell. These values outperformed a CNTS-based gate-free visible photodetector.
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Submitted 29 August, 2023; v1 submitted 6 August, 2023;
originally announced August 2023.
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Observation of Mesoscopic Clathrate Structures in Ethanol-Water Mixtures
Authors:
Wei-Hao Hsu,
Tzu-Chieh Yen,
Chien-Chun Chen,
Chih-Wen Yang,
Chung-Kai Fang,
Ing-Shouh Hwang
Abstract:
Water-alcohol mixtures exhibit many abnormal physicochemical properties, the origins of which remain controversial. Here we use transmission electron microscopy (TEM), nanoparticle tracking analysis (NTA), and atomic force microscopy (AFM) to study ethanol-water mixtures. TEM reveals mesoscopic clathrate structures with water molecules forming a crystalline matrix hosting a high density of tiny ce…
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Water-alcohol mixtures exhibit many abnormal physicochemical properties, the origins of which remain controversial. Here we use transmission electron microscopy (TEM), nanoparticle tracking analysis (NTA), and atomic force microscopy (AFM) to study ethanol-water mixtures. TEM reveals mesoscopic clathrate structures with water molecules forming a crystalline matrix hosting a high density of tiny cells. The presence of these mesoscopic clathrate structures is further supported by a refractive index of 1.27+-0.02 at 405 nm measured via NTA and the hydrophilic nature of the mesoscopic structures implied by AFM observations, explaining many long-standing puzzles related to water-alcohol mixtures.
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Submitted 7 April, 2022;
originally announced April 2022.
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Clustered Geometries Exploiting Quantum Coherence Effects for Efficient Energy Transfer in Light Harvesting
Authors:
Qing Ai,
Tzu-Chi Yen,
Bih-Yaw Jin,
Yuan-Chung Cheng
Abstract:
Elucidating quantum coherence effects and geometrical factors for efficient energy transfer in photosynthesis has the potential to uncover non-classical design principles for advanced organic materials. We study energy transfer in a linear light-harvesting model to reveal that dimerized geometries with strong electronic coherences within donor and acceptor pairs exhibit significantly improved effi…
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Elucidating quantum coherence effects and geometrical factors for efficient energy transfer in photosynthesis has the potential to uncover non-classical design principles for advanced organic materials. We study energy transfer in a linear light-harvesting model to reveal that dimerized geometries with strong electronic coherences within donor and acceptor pairs exhibit significantly improved efficiency, which is in marked contrast to predictions of the classical Förster theory. We reveal that energy tuning due to coherent delocalization of photoexcitations is mainly responsible for the efficiency optimization. This coherence-assisted energy-tuning mechanism also explains the energetics and chlorophyll arrangements in the widely-studied Fenna-Matthews-Olson complex. We argue that a clustered network with rapid energy relaxation among donors and resonant energy transfer from donor to acceptor states provides a basic formula for constructing efficient light-harvesting systems, and the general principles revealed here can be generalized to larger systems and benefit future innovation of efficient molecular light-harvesting materials.
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Submitted 22 July, 2013;
originally announced July 2013.