Sol-gel Synthesis of LaAlO₃; Epitaxial Growth of LaAlO₃ Thin Films on SrTiO₃(100)

A LaAlO₃ precursor solution was prepared via an all alkoxide sol-gel route. The solution of lanthanum methoxyethoxide and aluminum methoxyethoxide in 2-methoxyethanol was prepared via ligand exchange starting from lanthanum isopropoxide and aluminum sec-butoxide and was used to make both LaAlO₃ powders and films. Complete hydrolysis of the solution formed a gel that yielded well-crystallized LaAlO₃ powders when fired in air at 800 °C. A partially hydrolyzed solution was spun-cast on SrTiO₃ (100) single crystal substrates. Epitaxial films of LaAlO₃ were subsequently formed during pyrolysis in O₂ at 800 °C in a rapid thermal annealing furnace for a total of 8 min. The films were strongly c-axis oriented, verified by x-ray rocking curve results from the (003) plane with full-width at half-maximum (FWHM) = 0.87°, and had good in-plane texture shown by a φ scan of the (202) plane with FWHM = 1.07°.