A high resolution synchrotron radiation core level photoemission study of the native oxides on In(0.53)G(0.47)As was carried out in order to determine the various oxidation states present on the surface. The thermal stability of the oxidation states was also investigated by annealing the samples in vacuum at temperatures ranging from 150 to 450 degrees C. As well as the widely reported oxidation states, various arsenic, gallium, and indium oxides, along with mixed phase gallium arsenic and indium gallium oxides are identified. Elemental binary oxides have been identified as residing at the oxide substrate interface and could play an important role in understanding the growth of metal oxide dielectric layers on the In GaAs surface, due to their apparent chemical stability. (C) 2010 American Institute of Physics. [doi:10.1063/1.3475499]