TEM micrographs showing thermal shrinking of silicon dioxide nanopore. (a) TEM micrograph of ~250 nm pore drilled with FIB in 300 nm thick oxide membrane. (b) TEM micrograph of the nanopore after 5 min of thermal shrinking at 1150°C. The diameter of the nanopore was ~150 nm. The wavy surface of the oxide at nanopore edges shows the shrinking process due to viscous flow of oxide. (c) Nanopore after 10 min. The diameter is ~20 nm. (d) Nanopore after another 10 min and 40 s showing the diameter of ~3 nm.
Asghar et al. Nanoscale Research Letters 2011 6:372 doi:10.1186/1556-276X-6-372