ZnRh 2 O 4 : A p-type semiconducting oxide with a valence band composed of a low spin state of Rh3+ in a 4d6 configuration

Abstract
It is demonstrated that a ZnRh 2 O 4 normal spinel with a band gap of ∼2.1 eV is a unique material as a p type wide-gap semiconductor. The electrical conductivity of the sputtered film was 0.7 S cm−1 at 300 K with no intentional doping. The electronic structure was investigated by photoemission and inverse photoemission measurements and indicated that the band gap is composed mainly of ligand field splitting of an octahedrally coordinated Rh 3+ octahedron between fully occupied t 2g 6 and empty e g 0 sets.