Adsorption controlled molecular beam epitaxy of rubidium barium bismuth oxide.

Measurements of the sticking coefficients for rubidium, barium and bismuth have been made during molecular beam epitaxy of (Rb,Ba)BiO3 on MgO. This simple cubic perovskite is a high temperature superconductor for Rb fractions between 0.4 and 0.5. The dependence of these sticking coefficients on substrate temperature, oxygen plasma conditions, and on incident flux composition indicate that in a narrow region of flux compositions, adsorption and desorption rates of bismuth and rubidium (and possibly barium) will control the stoichiometry of the film.