Ion-beam sculpting
Ion-beam sculpting is a two-step way to make solid-state nanopores. First, a hole is created with a focused ion beam (FIB), usually about 100 nm wide, though smaller holes are possible. This hole can be open all the way through or only partially (blind).
Second, the hole is refined using one of three sculpting methods:
- Broad-area argon ion exposure: A wide argon beam is applied, often from the back side, to slowly remove material and move atoms toward the hole’s edge. A detector watches the ions passing through the membrane, and the process stops when the current indicates the hole has reached the desired size (sometimes as small as 1–10 nm). This method can produce smaller, smoother holes than FIB alone and works even if the hole isn’t fully through yet.
- TEM exposure: An electron beam from a transmission electron microscope finishes closing the hole. This method is slow (often over an hour for a 100 nm hole) but allows you to watch the hole shrink in real time. Hydrocarbon buildup helps the hole close.
- FIB imaging/closing: After milling, the hole can be imaged with the FIB, which can also help close it. However, the resulting holes are often jagged, not perfectly circular, and size control is less precise because the imaging and sputtering occur simultaneously.
A newer commercial FIB-based sculpting approach can produce smoothly circular nanopores below 10 nm and can sculpt several pores at once, depending on the instrument.
Throughout the process, real-time feedback is key: monitoring the ion current as the hole narrows lets researchers stop exactly when the desired pore size is reached.
This page was last edited on 2 February 2026, at 23:24 (CET).