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The semiconductor field-effect platform is a powerful tool for chemical and biological sensing with direct electrical readout. In this work, the field-effect capacitive electrolyte-insulator-semiconductor (EIS) structure - the simplest field-effect (bio-)chemical sensor - modified with citrate-capped gold nanoparticles (AuNPs) has been applied for a label-free electrostatic detection of charged molecules by their intrinsic molecular charge. The EIS sensor detects the charge changes in AuNP/molecule inorganic/organic hybrids induced by the molecular adsorption or binding events. The feasibility of the proposed detection scheme has been exemplarily demonstrated by realizing capacitive EIS sensors consisting of an Al-p-Si-SiO2-silane-AuNP structure for the label-free detection of positively charged cytochrome c and poly-d-lysine molecules as well as for monitoring the layer-by-layer formation of polyelectrolyte multilayers of poly(allylamine hydrochloride)/poly(sodium 4-styrene sulfonate), representing typical model examples of detecting small proteins and macromolecules and the consecutive adsorption of positively/negatively charged polyelectrolytes, respectively. For comparison, EIS sensors without AuNPs have been investigated, too. The adsorption of molecules on the surface of AuNPs has been verified via the X-ray photoelectron spectroscopy method. In addition, a theoretical model of the functioning of the capacitive field-effect EIS sensor functionalized with AuNP/charged-molecule hybrids has been discussed.
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http://dx.doi.org/10.1039/c4nr05987e | DOI Listing |
ACS Appl Mater Interfaces
August 2025
Department of Physics, University of Seoul, Seoul 02504, Republic of Korea.
In this study, we demonstrate that a room-temperature reactively sputtered aluminum oxynitride (AlON) overlayer enables both effective doping and pronounced threshold voltage hysteresis in multilayer MoS FETs, while preserving field-effect mobility. Compared to conventional AlO, the AlON layer introduces trap states that are energetically aligned with the conduction band of MoS, facilitating charge exchange across the heterointerface. Capacitance-voltage measurements confirm that nitrogen incorporation reduces the effective fixed charge density, enabling mobility-preserving operation without thermal annealing.
View Article and Find Full Text PDFSci Rep
July 2025
Faculty of Electrical Engineering and Communication, Brno University of Technology, Technicka 3082/12, Brno, 616 00, Czech Republic.
This paper presents two discrete circuit solutions for realizing passive, electronically adjustable constant-phase elements, specifically half-order capacitors with a -45° phase shift. Fractional-order capacitors with electronically adjustable pseudocapacitance are especially useful for designing tunable filters and oscillators. The ability to adjust pseudocapacitance electronically and continuously is a major improvement over traditional passive solutions.
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June 2025
Engineering Science and Mechanics, The Pennsylvania State University, University Park, PA, USA.
Silicon has enabled advancements in semiconductor technology through miniaturization, but scaling challenges necessitate the exploration of new materials. Two-dimensional (2D) materials, with their atomic thickness and high carrier mobility, offer a promising alternative. Although significant progress has been made in wafer-scale growth, high-performance field-effect transistors and circuits based on 2D materials, achieving complementary metal-oxide-semiconductor (CMOS) integration remains a challenge.
View Article and Find Full Text PDFAdv Sci (Weinh)
September 2025
Institute of Electronics, National Yang Ming Chiao Tung University, Hsinchu, 30010, Taiwan.
Carbon nanotubes (CNTs) present considerable potential as next-generation logic switches owing to their ultra-thin structure and exceptional electrical properties. Although recent advancements have achieved impressive direct current (DC) performance in individual devices, research on the architectural design of CNT-based transistors remains limited. This gap is critical, as device architecture directly influences power consumption and switching speed at the circuit level.
View Article and Find Full Text PDFMicromachines (Basel)
April 2025
Key Laboratory of High Performance Scientific Computation, Xihua University, Chengdu 610039, China.
This paper proposes a 1200V 4H-SiC MOSFET incorporating a High-K dielectric-integrated fused source-gate (HKSG) structure, engineered to concurrently enhance the third-quadrant operation and high-frequency figure of merit (HF-FOM). The High-K dielectric enhances the electric field effect, reducing the threshold voltage of the source-gate. As a result, the reverse conduction voltage drops from 2.
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