ABSTRACT
The potential barrier at the semiconductor surface in contact with a metal or an electrolyte is a determining factor in solid-state device physics and in photoelectrochemistry. In this chapter, the authors treat quantitatively the shape of the barrier at the semiconductor surface in contact with metal. They stress the importance of the capacitance measurements that reveal different properties of the semiconductor and the barrier. The authors discuss small-size nanostructures, such as nanoparticles and nanowires, first considering the depletion layer at the internal surface, and then the nanostructures that operate by homogeneous displacement of the Fermi level. They provide a detailed view of the properties of semiconductor/electrolyte junctions that are used in photoelectrochemical cells. A general energy diagram is presented to combine the interpretation of the electrochemical measurement with the changes of the local vacuum level. The displacement of the Fermi levels of the separate materials, toward the Fermi level equilibration, occurs in both, semiconductor and metal.
