Analysis of Electronic States of New Solution-processed, Unusual P-type Oxides by Using Hard X-ray Photoelectron Spectroscopy (HXPES)

Abstract

Our unusual p-type oxide, Ni-Rh-O, showed unprecedentedly low resistivity (10^-4 – 10^-5 ohm cm) and metallic conduction. HXPES indicated nickel in the Ni²⁺ state while rhodium mainly in the Rh⁰ state, suggesting a phase composition of Rh_5.14(NiO)(Rh₂O₃)_0.13C_0.16. A Rh⁰ core-oxide shell-structure was proposed to explain the unusual conduction properties.