Degradation mechanism of vanadium oxide films when grown on Y-stabilized ZrO2 above 500 oC

Abstract

Although vanadium oxide (VOx) phases are thermodynamically similar, Y-stabilized ZrO2 (YSZ) substrates show selective growth as single-crystalline films. However, in this study, we find that the films degrade with the formation of nanoislands when evaporating VOx onto YSZ at a substrate temperature >500 °C. The nanoislands are epitaxial, i.e., Y-doped VO2(R) at an oxygen partial pressure (Formula presented.) < 30 mTorr, and YVO4 at (Formula presented.) > 50 mTorr. Energy-dispersive X-ray spectroscopy shows that the rapid diffusion of vanadium and yttrium plays a critical role in film degradation. The degradation mechanism revealed herein guides the fabrication of VOx films for energy and electronic device applications. © 2019 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim