Narrow growth window for stoichiometric, layer-by-layer growth of LaAlO 3 thin films using pulsed laser deposition
Abstract We study the structure and surface morphology of the 100 nm homoepitaxial LaAlO 3 films grown by pulsed laser deposition in a broad range of growth parameters. We show that there is a narrow window of growth conditions in which the stoichiometric, bulk-like structure is obtained while maintaining a 2-dimensional (2D) layer-by-layer growth mode. In our system, these optimum growth conditions are 100 mTorr background pressure with laser energy density 1.5–2 J/cm 2 . The sensitivity to growth conditions of the stoichiometry and structure of LaAlO 3 films can have a crucial role in the 2-D electron gas formed at the LaAlO 3 /SrTiO 3 interface.
Finding environmentally gentle methods to graft Lewis acid on the surface of mesoporous materials is a topic of current interest. Herein we describe the optimization of a preparation procedure of a mesoporous silica-supported ErIII catalyst using the microwave-assisted post-calcination functionalization of Mobil Composition of Matter-41 silica as the key step. The required time for functionalization was reduced from several hours to 10 min using sealed-vessel microwave technology. Control experiments using conventional heating at the same temperature demonstrated that the rate increase is owing to a simple thermal/kinetic effect as a result of the higher reaction temperature. The resulting ErIII catalyst was tested for the first time as a catalyst in the continuous flow deprotection of benzaldehyde dimethylacetal and a complete leaching study was performed.