Fig. 2.

SEM images of cross-sectional profiles of nanochannels on the Si master with different aspect ratio. Nanochannels were milled by FIB rectangular mode, with 100 nm fixed setting width and setting depth ranging from 100 nm to 500 nm. When milled deeper by FIB, nanochannel cross-sectional profile changes from U-shaped to sharp tip V-shaped, which makes UV-resin solution hard to fill at the very bottom. SEM images were taken with a tilt angle of 52°.