Generation of Highly n-Type Titanium Oxide Using Plasma Fluorine Insertion

True n-type doping of titanium oxide without formation of midgap states would expand the use of metal oxides for charge-based devices. We demonstrate that plasma-assisted. fluorine insertion passivates defect States and that fluorine acts as an n-type donor in titanium oxide. This enabled us to modify the Fermi level and transport properties of titanium oxide outside the hits of O vacancy doping. The origin of the electronic structure modification is explained by ab initio calculation.