Niobium tips for use in scanning tunneling microscope (STM) light emission
measurements have been fabricated by an electrochemical etching method. The
typical radius of curvature of the tip is less than 100 nm. The Nb tip has
been demonstrated to be capable of producing STM images of highly oriented
pyrolytic graphite and Au(110)-(2x1) surfaces with atomic spatial resoluti
on. It has been confirmed by STM light emission spectroscopy that the front
of the Nb tip becomes superconducting for temperatures below the supercond
ucting transition temperature of Nb. (C) 2001 American Institute of Physics
.