X-ray photoelectron spectroscopic and secondary ion mass spectroscopic examinations of metallic-lithium-activated donor doping process on La0.56Li0.33TiO3 surface at room temperature

The donor doping process at the interface between the cation-deficient La0.56Li0.33TiO3 and lithium was elucidated by x-ray photoelectron spectroscopy (XPS) and secondary ion mass spectroscopy (SIMS). XPS revealed a chemical shift (∼1.48eV) from the main peak of Ti4+ 2p3∕2 toward the low energy side, due to the conversion of 12% Ti4+ to Ti3+. The SIMS analysis indicates that a local electric field was responsible for the insertion of oxidized Li+6 isotope ions. The doping with Ti3+ donors, accompanying the insertion of Li+ ions into cation vacancies of La0.56Li0.33TiO3, yields the n-type semiconducting characteristics at room temperature.