Fig. 5.

(a) PMMA enclosed nanochannels fabricated using proton beam writing coupled with thermal bonding, and (b) high magnification view of one of the buried channels. The channels are 200 nm wide and 2 μm deep. The proton beam was a 2 MeV energy beam that consisted of a 200 × 300 nm² spot size and was scanned over a 2 μm thick layer of PMMA layer spin coated onto a 50 μm Kapton film. Reprinted with permission from Shao et al. (2006).¹⁸⁸