Highly controllable fabrication of fiber probe for photon scanning tunneling microscope

Abstract

Summary: A selective chemical etching was used to fabricate fiber probes for the photon scanning tunneling microscope (PSTM). The cladding diameter of the fiber probe was controlled by varying the first-step etching time. The cone angle of the fiber probe tip was controlled by varying the doping ratio of the fiber and the composition of the etching solution. A cladding diameter of 8 µm and a tip diameter of about 3 nm were fabricated. The smallest cone angle was 14°.

Fiber-Optic Nanosensors for Chemical Detection

“…It was found that tip dimensions are influenced by a volume ratio of HF and NH4F in etching solutions and by etching time [53]. It is worth mentioning that in addition to etching solutions containing HF (usually approximately 50% wgt.…”

“…It is worth mentioning that in addition to etching solutions containing HF (usually approximately 50% wgt. ), buffered etching aqueous solutions employing HF and NH 4 F have also been used for the preparation of fiber nanotips [53]. Chemical reactions during etching with such etching solutions can be generally described by Equations ( 1) and ( 2) and by Equations ( 3) and (4) as well.…”

“…It was found that tip dimensions are influenced by a volume ratio of HF and NH 4 F in etching solutions and by etching time [53].…”