Figure 1: Photograph of a mercury drop junction
Shown is a two-terminal junction, where one electrode is a mercury drop covered with a standard SAM such as a C12 alkanethiolate (top) and the other is a sample metal covered with one of a series of SAMs of interest (bottom). In this junction, the two SAMs are brought in contact with each other; hence, the distance of separation between the two metal surfaces is at the molecular scale.