Hall mobility manipulation in TiO_2-x semiconductor films by hydrogen-ion irradiation

The effects of different irradiation doses of hydrogen ions on TiO_2-x semiconductor films were investigated. The total doses were controlled between ~10¹⁴ and ~10¹⁵ atom/cm² at an acceleration energy of 110 keV. The Hall mobility was manipulated by changing the irradiation dose while the carrier concentration was not. The amorphous crystal structure was consistently maintained upon irradiation. The electronic structures of the molecular orbitals in the conduction band were modified, and the band edge states below the conduction band increased with increasing irradiation dose. These changes in electronic structure were correlated to the chemical bonding states and could lead to variations in the Hall mobility without a structural transformation.