Degradation Mechanism of Vanadium Oxide Films When Grown on Y‐Stabilized ZrO₂ Above 500 °C

Although vanadium oxide (VO_x) 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 VO_x onto YSZ at a substrate temperature >500 °C. The nanoislands are epitaxial, i.e., Y‐doped VO₂(R) at an oxygen partial pressure < 30 mTorr, and YVO₄ at > 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 VO_x films for energy and electronic device applications.