Abstract
The formation of interfaces between magnesium(Mg) and the organic molecular semiconductor tris(8-hydroxy-quinoline) aluminum ( Alq 3 ) is studied via ultraviolet photoemissionspectroscopy. The morphology and electronic structure of Mg-on-Alq 3 and Alq 3 -on-Mg interfaces are compared. The energy of the Alq 3 molecular levels is determined in both cases with respect to a reference Fermi level as a function of interface formation. The difference in injection characteristics between the two interfaces is examined in terms of differences in interface morphology and of electronic gap states induced by the diffusion of Mg at the Mg/Alq 3 interface.