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Abstract

The interaction of aluminium with cleaved GaP(100) surfaces is important in the investigation of Schottky barrier formation since ideal Schottky behaviour has been reported for a number of metals on GaP(110). Al-GaP(110) provides an interesting example of a reactive interface, with limited Al-Ga exchange reaction occurring at room temperature (RT). Metal reactivity has been invoked as a possible cause of the deviation from the classical Schottky model reported for this interface at RT. We present high resolution core level photoemission data recorded with synchrotron radiation for the interfaces formed at room and low temperature (LT). The study of interface evolution is based on intensity and line shape analysis of the Ga(3d) and Al(2p) core level photoemission features. We investigate the reactions produced at the interface, model the evolving interfacial morphology and assess possible changes of reactivity. Our results show that the cation exchange reaction is not strongly reduced at LT whereas the growth mode of the aluminium layer and the formation of gallium interface species are significantly affected by the substrate temperature. Results are discussed in comparison with the widely studied Al-GaAs(110) and Al-InP(110) systems.