High Crystallinity CuScO_2 Delafossite Films Exhibiting Ultraviolet Photoluminescence Grown by Vapor-Liquid-Solid Tri-phase Epitaxy

摘要

We have grown direct wide-bandgap CuScO_2 thin films on MgAI_2O_4(111) substrates by tri-phase epitaxy employing molten Bi-0 flux on the growth surface. The full width at half maximum of (0006) rocking curve is as narrow as 0.005 degrees, an order of magnitude narrower than those grown by conventional pulsed laser deposition (PLD). Transmission electron microscopy confirms the scarcity of defect structures or precipitates, which are of high density in PLD films. The films exhibit sharp near-bandedge photoluminescence at 3.3 eV, which is absent in PLD films.