Porous nanocrystalline silicon (pnc-Si) membranes are a new class of solid-state ultra-thin membranes with promising applications ranging from biological separations to use as a platform for electron imaging and spectroscopy. Because the thickness of the membrane is only 15-30 nm, on the order of that of the molecules to be separated, mass transport through the membrane is greatly enhanced. For applications involving molecular separations, it is crucial that the membrane is highly permeable to some species while being nearly impermeable to others. An important approach to adjusting the permeability of a membrane is by changing the size and density of the pores. With pnc-Si, a rapid thermal treatment is used to induce nanopore formation in a thin film of nanocrystalline silicon, which is then released over a silicon scaffold using an anisotropic etchant. In this study, we examine the influence of thin film deposition and thermal treatment parameters on pore size and density.
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http://dx.doi.org/10.1088/0953-8984/22/45/454134 | DOI Listing |
Nanomaterials (Basel)
January 2025
Department of Physics and Astronomy, University College London, Gower Street, London WC1E 6BT, UK.
We used density functional theory with a hybrid functional to investigate the structure and properties of [4H] (hydrogarnet) defects in -quartz as well as the reactions of these defects with electron holes and extra hydrogen atoms and ions. The results demonstrate the depassivation mechanisms of hydrogen-passivated silicon vacancies in -quartz, providing a detailed understanding of their stability, electronic properties, and behaviour in different charge states. While fully hydrogen passivated silicon vacancies are electrically inert, the partial removal of hydrogen atoms activates these defects as hole traps, altering the defect states and influencing the electronic properties of the material.
View Article and Find Full Text PDFACS Appl Mater Interfaces
January 2025
Anhui Huasun Energy Company, Limited, Xuancheng 242000, China.
A rear emitter with a p-type boron-doped hydrogenated amorphous silicon/nanocrystalline silicon [a-Si:H(p)/nc-Si:H(p)] stack was prepared for the silicon heterojunction (SHJ) solar cell to improve its short-circuit current density (). CO plasma treatment (CO PT) was applied to a-Si:H(p) to facilitate the crystallization of the subsequently deposited nc-Si:H(p). To evaluate the effect of the CO PT, two different nc-Si:H(p) layers with low and high crystallinity (χ) were investigated.
View Article and Find Full Text PDFMicromachines (Basel)
November 2024
School of Materials Science and Chemical Engineering, Harbin University of Science and Technology, Harbin 150080, China.
Integrating nanocrystalline diamond (NCD) films on silicon chips has great practical significance and many potential applications, including high-power electronic devices, microelectromechanical systems, optoelectronic devices, and biosensors. In this study, we provide a solution for ensuring heterogeneous interface integration between silicon (Si) chips and NCD films using low-temperature bonding technology. This paper details the design and implementation of a magnetron sputtering layer on an NCD surface, as well as the materials and process for the connection layer of the integrated interface.
View Article and Find Full Text PDFACS Omega
December 2024
Institute of Photoelectronic Thin Film Devices and Technology, Nankai University, Tianjin 300350, China.
Silicon heterojunction (SHJ) solar cells, as one of the most promising passivated contact solar cell technologies of the next generation, have the advantages of high conversion efficiency, high open-circuit voltage, low-temperature coefficient, and no potential-induced degradation. For the single-side rear-emitter SHJ solar cells, the n-type carrier selective layer, which serves as the light-incident side, plays a pivotal role in determining the performance of heterojunction devices. Consequently, a superior n-doped layer should exhibit high optical transmittance and minimal optical absorption, along with a substantial effective doping level to guarantee the formation of dark conductivity (σ) and electron-transport capacity.
View Article and Find Full Text PDFSensors (Basel)
November 2024
National Institute for Research and Development in Microtechnologies-IMT Bucharest, 126A Erou Iancu Nicolae Street, 077190 Voluntari, Romania.
Plasma-enhanced chemical vapor deposition (PECVD) was used to obtain several graphite nanowall (GNW)-type films at different deposition times on silicon and copper to achieve various thicknesses of carbonic films for the development of electrochemical sensors for the detection of anthracene. The PECVD growth time varied from 15 min to 30 min to 45 min, while scanning electron microscopy (SEM) confirmed the changes in the thickness of the GNW films, revealing a continuous increase in the series. X-ray diffraction (XRD) analysis revealed that the crystallinity of the GNW film samples increased with increasing crystallite size and decreasing dislocation density as the deposition time increased.
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