( Ba 0.65 Sr 0.35 ) 1 − x La x TiO 3 (BSLT) thin films with different La concentrations have been deposited on Si field emitter arrays (FEAs) using sol-gel technology for field electron emission applications. The films exhibit the perovskite structure at low La substitution level (x≤0.5) and the pyrochlore phase at high La concentration (x≥0.75). The 30-nm-thick BSLT (x=0.25) thin film has higher crystallinity of perovskite structure in the surface region. An x-ray photoelectron spectroscopy study indicates that the oxygen vacancy concentration decreases with La substitution. With respect to the undoped Ba0.65Sr0.35TiO3 thin film, the Fermi level shifts down for the BSLT sample with x=0.1 ascribed to the decreasing oxygen vacancy concentration, and then shifts up for the BSLT sample with x=0.25 attributed to the increasing La substitution level. In highly doped films with an x value over 0.5, it shifts down again associated with the second pyrochlore phase formation. The best enhancement in field emission is found for the BSLT-coated (x=0.25) Si FEAs due to the improved perovskite structure in the surface region and up-moved Fermi level of the coating.