First-principles simulations on bulk Ta2O5 and Cu/Ta2O5/Pt heterojunction: Electronic structures and transport properties

Electronic structures and transport properties of bulk Ta2O5 and Cu/Ta2O5/Pt heterojunction have been studied from first principles. Of the two room-temperature phases of bulk Ta2O5, β-, and δ-Ta2O5, our calculated results showed that the β phase has much narrower band gap than the δ-Ta2O5. For Cu/δ-Ta2O5/Pt heterojunction, the p-type Schottky barriers between the Cu (Pt) and Ta2O5 were estimated as 0.9–1.2 eV. Both the standard density-functional calculation and the nonequilibrium Green’s function showed that no conducting channels were formed from Cu to Pt through δ-Ta2O5.