Georgia Institute of Technology College of Sciences

Scanning-tunneling-microscope images are obtained for freshly cleaved graphite in air. Large flat regions of graphite are observed, as well as steps between graphite layers. Tunneling spectroscopy (TS) shows a lower surface density of states for graphite near surface defects at the bias voltages tested. This indicates that TS is sensitive to the state of the substrate and this may have implications regarding the use of TS to reveal detailed information about the presence of molecular adsorbates on surfaces with defects.