Self-regulating plasma-assisted growth of epitaxial BaBiO3 thin-film on SrTiO3-buffered Si(001) substrate

Abstract

The BaBiO3 perovskite oxide is an interesting material system because of its superconductivity when p-doped and the predicted topological insulating nature when n-doped. Single crystalline BaBiO3 films are grown by molecular beam epitaxy with high quality utilizing the adsorption-controlled regime, where volatile Bi is supplied in excess in the presence of oxygen radicals. BaBiO3 films are integrated on Si(001) substrates through growth on a SrTiO3(001) buffer layer. Despite the 11.77% lattice mismatch, by systematically varying growth parameters, such as plasma conditions, substrate temperature, and metallic fluxes, a growth window for the BaBiO3 is well-established. Within the optimum growth window, films are stoichiometric and of high crystalline quality based on the different physical characterization techniques. The development of robust layers is facilitated by accessing the self-regulating regime, where only the stoichiometric quantity of Bi sticks during the epitaxy.