To appreciate the sensitivity of the Barents Sea benthic system to the observed changes in surface primary production, there is a need to better understand this benthic–pelagic coupling. These changes will potentially alter the composition of phytodetritus deposited at the seafloor, which acts as a biogeochemical reactor and is pivotal in the recycling of key nutrients, such as silicon (Si). These physical changes have resulted in rapid ecosystem adjustments, manifesting as a northward migration of temperate phytoplankton species at the expense of silica-based diatoms. Over recent decades the highest rates of water column warming and sea ice loss across the Arctic Ocean have been observed in the Barents Sea. EELS data reveal the atomic composition of bare and HfO2-coated pores. However, coating pores with a conformal 1 nm-thick hafnium oxide layer prevents expansion in 1 M KCl, in stark contrast to bare SiN The etching process occurs where the membrane was exposed to the electron beam and can result in pore formation. Pore expansion is caused by etching of the Si/SiO2 pore walls, which resembles the dissolution of silicon found in minerals such as silica (SiO2) in salty ocean water. Using electron energy loss spectroscopy (EELS), we observe a N-deficient region around the edges of TEM-drilled pores. TEM confirms the range of diameter etch rates from ionic measurements. Pore diameters increase with time, and diameter etch rate increases with electrolyte concentration from Δd/Δt ∼ 0.2 to ∼ 3 nm/day for 0.01 to 3 M KCl, respectively.
We store them in various electrolyte solutions (KCl, LiCl, MgCl2) and record open pore conductance over months to quantify pore stability. Pores are fabricated using a transmission electron microscope (TEM) and/or electron beam lithography (EBL) and reactive ion etching (RIE), with diameters from 2 to 80 nm. We report the lifetime and durability of pores and porous arrays in 10 to 100 nm-thick, low-stress silicon nitride (SiN Solid-state nanopores are preferable over their biological counterparts for applications requiring durability and operation under a wider range of external parameters, yet few studies have focused on optimizing their robustness. Nanopores are promising for many applications including DNA sequencing and molecular filtration.
0 kommentar(er)
