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Silicon (Si) alkaline etching constitutes a fundamental process in the semiconductor industry. Although its etching kinetics on plain substrates have been thoroughly investigated, the kinetics of Si wet etching in nanoconfinements have yet to be fully explored despite its practical importance in three-dimensional (3-D) semiconductor manufacturing. Herein, we report the systematic study of potassium hydroxide (KOH) wet etching kinetics of amorphous silicon (a-Si)-filled two-dimensional (2-D) planar nanochannels. Our findings reveal that the etching rate would increase with the increase in nanochannel height before reaching a plateau, indicating a strong nonlinear confinement effect. Through investigation using etching solutions with different ionic strengths and/or different temperatures, we further find that both electrostatic interactions and the hydration layer inside the nanoconfinement contribute to the confinement-dependent etching kinetics. Our results offer fresh perspectives into the kinetic study of reactions in nanoconfinements and will shed light on the optimization of etching processes in the semiconductor industry.
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http://dx.doi.org/10.1021/acs.langmuir.4c00056 | DOI Listing |
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August 2025
Department of Physics, National University of Singapore, Singapore, 117551, Singapore.
Orientation-dependent wet chemical etching of crystalline germanium (c-Ge) is essential for the fabrication of next-generation complementary metal oxide semiconductor (CMOS) devices. Here, using a combination of conventional and in situ liquid-phase transmission electron microscopy (TEM) imaging, we reveal the details of the wet etching process of c-Ge nanostructures and identify critical parameters that control the etching rates along different crystalline directions. We demonstrate that etching behavior can be changed from isotropic to anisotropic etching (i.
View Article and Find Full Text PDFJ Funct Biomater
July 2025
CNR NANOTEC-Institute of Nanotechnology, c/o Campus Ecotekne, 73100 Lecce, Italy.
Cell migration assays provide valuable insights into pathological conditions, such as tumor metastasis and immune cell infiltration, and the regenerative capacity of tissues. In vitro tools commonly used for cell migration studies exploit commercial transwell systems, whose functionalities can be improved through engineering of the pore pattern. In this context, we propose the fabrication of a transwell-like device pursued by combining the proton beam writing (PBW) technique with wet etching onto thin layers of polydimethylsiloxane (PDMS).
View Article and Find Full Text PDFJ Vis Exp
August 2025
Wyant College of Optical Sciences, University of Arizona, Tucson.
Silicon nitride membranes are a widely used optomechanical resonator platform, offering high mechanical Q, low optical loss, and enhanced optomechanical coupling using a panoply of strain, phononic-crystal, and photonic-crystal engineering techniques. Despite their ubiquity, fabrication and characterization of silicon nitride membranes often rely on tacit knowledge shared between research groups. This article presents a detailed video walk-through of the design, fabrication, and characterization of a contemporary silicon nitride membrane resonator (specifically, a centimeter-scale Si3N4 nanoribbon supporting torsional modes with Q-factors exceeding 10 at room temperature).
View Article and Find Full Text PDFACS Appl Mater Interfaces
August 2025
MOE Key Laboratory of Thermo-Fluid Science and Engineering, School of Energy and Power Engineering, Xi'an Jiaotong University, Xi'an 710049, China.
The rapid removal of condensate droplets is important for achieving stable dropwise condensation, thus improving the thermal efficiency of condensing equipment. The microstructure on the condensing surface can facilitate the departure of droplets. However, most existing microstructures are arrays of a single structure, which can only generate a single directional Laplace pressure gradient.
View Article and Find Full Text PDFNanomaterials (Basel)
July 2025
School of Materials Science and Engineering, South China University of Technology, Guangzhou 510640, China.
CdTe nanocrystals (NCs) have emerged as a promising active layer for efficient thin-film solar cells due to their outstanding optical properties and simple processing techniques. However, the low hole concentration and high resistance in the CdTe NC active layer lead to high carrier recombination in the back contact. Herein, we developed a novel 2-iodothiophene as a wet etching solution to treat the surface of CdTe NC.
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