Stabilization of the β-phase Bi2O3 (201) thin film by an ultrathin Bi(001) seeding layer

The bismuth oxide films prepared by the physical evaporation of Bi2O3 or the thermal oxidation of Bi usually display amorphous or ploycrystalline structures. There has been only few reports on the fabrication of the pure beta-phase Bi2O3 film which is accomplished under extreme conditions. In this study, an innovative method is introduced to fabricate the beta-phase Bi2O3 film with (201) preferred orientation by utilizing an ultrathin Bi(001) seeding layer. The Bi/BiOx bylayers were prepared at room temperature first and then annealed in oxygen ambient. The formation of (201) orientation of Bi2O3 film was strongly related to the oxygen pressure during annealing. Compared with the bismuth oxide obtained directly from the thermal oxidation of the bismuth film, the beta-phase Bi2O3 (201) film displayed a smooth surface and well crystallinity.