A coherent explanation of the Fermi level
pinning phenomenon in Schottky barriers has escaped the grasp of physicists
and engineers for decades. As a result, our understanding of the related
problem of band alignment at other technologically important interfaces,
such as the semiconductor heterojunctions, the oxide-semiconductor interfaces,
and the metal-molecule interfaces, also suffered. In this talk, it
is suggested that concepts and methods historically used by molecular chemists
may shed light on the issue of band offset at solid interfaces. Specifically,
it is shown that the electrochemical potential equalization (ECPE) method
and the atoms-in-molecules (AIM) method provide a good basis for understanding
the Fermi level pinning problem and the heterojunction band offset problem,
respectively