Abstract
The metal/alpha-Ge2Sb2Te5 interface was examined using x-ray photoelectron spectroscopy. Doping Ge2Sb2Te5 with nitrogen leads to an increase in hole barrier height at the interface between metals and nitrogen-doped Ge2Sb2Te5. Hole barrier height at metal/alpha-Ge2Sb2Te5 interface is reduced slightly by increasing the work function of the metal. We observed significant pinning of metal Fermi level toward the valence band energy of undoped or nitrogen-doped Ge2Sb2Te5. This leads to low hole barrier height and good Ohmic contact formed between metals and alpha-Ge2Sb2Te5. (C) 2009 American Institute of Physics. [doi:10.1063/1.3263953]