  A series of experiments were conducted using the STM instrument, which
involves a conducting tip probe to analyse sample surfaces by measurements of a
tunnelling current. In this experiment, STM was used to (1) determine the
lattice constant of Highly Oriented Pyrolytic Graphite (HOPG) by acquiring
atomic resolution images of its surface, (2) measure the work functions of gold
(Au) and HOPG samples using the STS mode and, (3) compare the variation of the
Local Density of States (LDOS) of gold, graphite and Silicon (Si) samples with
respect to bias voltage V. Experimental values of the lattice constant of HOPG
and work functions for gold and graphite were determined as 0.27 +/- 0.2 nm,
0.7 +/- 0.1 eV and 0.5 +/- 0.1 eV respectively. The lattice constant deviated
slightly from the literature value of 0.246 nm, whereas the work functions
deviated significantly from the literature values of 5.40 eV for gold and 4.62
eV for graphite. The LDOS for gold was found to be the highest, followed by
graphite, then silicon. These findings will be discussed.
