The R-SPE procedure for the growth of single-crystalline InGaO₃(ZnO)₅ films is as follows. 
Step 1: a ZnO epitaxial layer was grown on a (111)-YSZ substrate by PLD at 600^oC. Thickness of the ZnO epitaxial layer was ~2 nm, evaluated by grazing incidence X-ray reflectivity (GIXR) measurements. 
Step 2: a 150-nm-thick polycrystalline InGaO₃(ZnO)₅ film was deposited on the ZnO epitaxial layer at room temperature (25^oC)(a). X-ray photoelectron spectroscopy (XPS) revealed that the chemical composition of the deposited InGaO₃(ZnO)₅ film differs insignificantly from that of the target. 
Step 3: The resultant bilayer film was fully covered by placing a YSZ plate (10 mm x 10 mm x 0.5 mm) on the film surface to suppress vaporization of ZnO and In₂O₃ during the annealing in step 4. 
Step 4: The bilayer film was annealed at 1400^oC for 0.5 h in air (d). [(b) 800^oC, (c)1000^oC]
Step 5: The film was cooled down to room temperature in the furnace. Finally, a YSZ cap plate was removed and the surface of the annealed film looks very clean without chemical reaction with the YSZ plate.