2012 BFY Abstract Detail Page
Previous Page |
New Search |
||W38 - Scanning Tunneling Microscopy for Advanced Undergraduate Physics Labs
||The Scanning Tunneling Microscope illustrates principles of modern physics in a way that that is not achievable by any other instrument. The primary reason for this is the fact that the STM operates on the principle of "electron tunneling" and allows the user to probe the real space atomic structures of conductors and examine the local density of states (LDOS) of surfaces.
This demonstration will involve the use of simple, readily available starting materials with minimal sample preparation and will obtain real space atomic resolution of the metal-like substance, highly ordered pyrolytic graphite (HOPG). The lab will be divided into two segments, the first involving the imaging of graphite to see the individual atoms using the easyScan STM. Image analysis will be performed by identifying the hexagonal "honeycomb" pattern of carbon atoms and calculating the atom-to-atom distance. The second segment will involve obtaining current-voltage (I-V) curves on HOPG and its subsequent interpretation. The demonstration will also show how to construct and the differential conductance (dI/dV) of the I-V curve. Lastly, we will obtain I-V curves for a semiconductor and contrast the features with those obtained for the conductor, HOPG.