Skip to main content
. 2009 Nov 30;106(50):21039–21044. doi: 10.1073/pnas.0911450106

Fig. 3.

Fig. 3.

Examples of different pore shapes in tracked-etched SiN membranes. The etching time controls the pore radius and partially the membrane thickness. (A and B) Cross-sections of membranes containing conically shaped nanopores. The pores were obtained by etching Bi-irradiated SiN films in H3PO4 for 40 min (A), and 50 min (B). (C) Cross-section of a membrane containing double-conical nanopores. The pores were obtained by etching Bi-irradiated SiN film in H3PO4 for 30 min. The film was suspended in the etchant so that the etching could occur freely from both sides. (D) TEM images of a nanopore fabricated by the ion track etching (ITE) technique together with a pore that was fabricated by e-beam drilling using TEM. The conical shape of the ITE nanopore is responsible for the distinct halo around the pore.