Large-Area Crystalline BaSnO3 Membranes with High Electron Mobilities

We demonstrate the synthesis of the high-mobility transparent conducting oxide La-doped BaSnO3 as freestanding nanomembranes. Membranes are fabricated by employing water-soluble sacrificial layers (Sr3Al2O6 and Ba3Al2O6) which are epitaxially grown on SrTiO3 (001) substrates by pulsed laser deposition. We find a high crack density for membranes released using Sr3Al2O6. However, the use of lattice-matched Ba3Al2O6 leads to large-area single crystal membranes with high electron mobilities. These results suggest the importance of lattice mismatch and internal strain within the sacrificial layer as important parameters for producing millimeter scale perovskite oxide nanomembranes with a high degree of crystallinity.