Au/GaN interface: Initial stages of formation and temperature-induced effects - art. no. 085308

Synchrotron radiation photoemission spectromicroscopy has been used to stud y the properties of an Au/GaN interface starting from an atomically clean G aN surface. The effects of Au coverage and temperature were examined. The r esults have demonstrated that annealing alters the height of the Schottky b arrier, formed after deposition of a 4-monolayer (ML) Au film at room tempe rature. The photoemission spectra indicate that these barrier changes shoul d be attributed to structural rearrangements of the Au film and to formatio n of a Au gallide interfacial layer, a product of the reaction between the Au and GaN above 500 degreesC. The photoemission images have revealed that spatial heterogeneity in the composition is developed at temperatures above 750 degreesC. The large spread of the Au/GaN barrier heights reported in t he literature was discussed considering the current theoretical concepts.