Epitaxial growth of MoO3 polymorphs and impacts of Li-ion electrochemical reactions on their structural and electronic properties

Abstract Two polymorphs of MoO 3 (orthorhombic α and monoclinic β phases) were epitaxially grown on the (100) plane of cubic perovskites by using pulsed-laser deposition. The electrochemical cells were implemented for investigating the impacts of Li-ion intercalation on each phase. Despite the most stable phase, α -MoO 3 films were transformed to an amorphous phase after a single electrochemical cycle. In contrast, the β -MoO 3 films indicated reversible cyclic voltammogram against repeated electrochemical cycles of intercalation and subsequent deintercalation, and remained in forms of the crystalline Li x MoO 3 . Systematic evolutions of electronic, optical, and structural properties of Li x MoO 3 films across insulator-to-metal transition are reported.