It is pointed out that, under most circumstances, current transport ch
aracteristics observed at Schottky barrier junctions cannot be used to
unambiguously identify the mechanism responsible for electron conduct
ion. This practice, however, is quite common and is shown to lead to a
n incorrect conclusion in a recent article [Z. Q. Shi and W. A. Anders
on, J. Appl. Phys. 72, 3803 (1992)].