We have measured current-voltage (IV) characteristics of Si(111)7 x 7-
Ag, Si(111)(square-root 3 x square-root 3)R30-degrees-Ag and Si(100)2
x 1-Ag interfaces, grown in ultrahigh vacuum (UHV). Our data strongly
suggest that their Schottky barrier heights (SBHs) are spatially non-u
niform. This non-uniformity may be attributed to structural and morpho
logical inhomogeneity at the interface. This demonstrates the importan
ce of interface structure and growth kinetics for determining macrosco
pic properties such as SBH.