Relation between barrier height and work function in contacts to selenium

In Se–Tl, Se–Cd, Se–Au, and Se–Te contacts prepared by evaporation on a crystallized selenium layer, Schottky barrier heights were measured from junction capacitance. These were found to decrease systematically with the work function of the contacting metal. From this variation, the density of interface states was estimated to be about 1014 cm−2 eV−1, assuming an interfacial layer thickness of 10 Å. The neutral level of the states was estimated to lie close to the valence band edge.