| Autor: |
Dutt S; Department of Materials Physics, Research School of Physics, The Australian National University, Canberra, ACT 2601, Australia., Karawdeniya BI; Department of Electronic Materials Engineering, Research School of Physics, The Australian National University, Canberra, ACT 2601, Australia., Bandara YMNDY; Department of Materials Physics, Research School of Physics, The Australian National University, Canberra, ACT 2601, Australia.; Research School of Chemistry, The Australian National University, Canberra, ACT 2601, Australia., Afrin N; Department of Materials Physics, Research School of Physics, The Australian National University, Canberra, ACT 2601, Australia., Kluth P; Department of Materials Physics, Research School of Physics, The Australian National University, Canberra, ACT 2601, Australia. |
| Abstrakt: |
Thin membranes are highly sought-after for nanopore-based single-molecule sensing, and fabrication of such membranes becomes challenging in the ≲10 nm thickness regime where a plethora of useful molecule information can be acquired by nanopore sensing. In this work, we present a scalable and controllable method to fabricate silicon nitride (Si x N y ) membranes with effective thickness down to ∼1.5 nm using standard silicon processing and chemical etching using hydrofluoric acid (HF). Nanopores were fabricated using the controlled breakdown method with estimated pore diameters down to ∼1.8 nm yielding events >500,000 and >1,800,000 from dsDNA and bovine serum albumin (BSA) protein, respectively, demonstrating the high-performance and extended lifetime of the pores fabricated through our membranes. We used two different compositions of Si x N y for membrane fabrication (near-stoichiometric and silicon-rich Si x N y ) and compared them against commercial membranes. The final thicknesses of the membranes were measured using ellipsometry and were in good agreement with the values calculated from the bulk etch rates and DNA translocation characteristics. The stoichiometry and the density of the membrane layers were characterized with Rutherford backscattering spectrometry while the nanopores were characterized using pH-conductance, conductivity-conductance, and power spectral density (PSD) graphs. |
