Figure 2.

Nonideal modified semiconductor surface. For steric reasons, the receptor molecules cannot occupy every site on the semiconductor surface, leaving many surface atoms with termination such as hydrogen. Additional nonidealities include (a) nonspecific interaction of the receptor molecules with the surface, (b) dangling bonds or semiconductor surface radicals, [(c) and (f)] nonspecific interaction of the surface with analytes, (d) voids and defects in the receptor molecule film, (e) suboxide, and (g) surface oxide.