Combinatorial Chemical Beam Epitaxy of Lithium Niobate Thin Films on Sapphire

A combinatorial chemical beam epitaxy technique was used to optimize deposition of {001} lithium niobate thin films on {001} sapphire substrates. Lithium tert-butoxide and niobium tetra-ethoxy di-methyl-amino-ethoxide were used as precursors. The highest quality films obtained exhibited rocking curve full-width at half-maximum values of about 0.03deg and lithium contents larger than estimated by Raman spectroscopy. High-resolution transmission electron microscopy observations revealed that the lithium niobate film consists of a buffer layer (thickness ) with a high density of defects above which the epitaxial lithium niobate film was obtained.