Mist chemical vapor deposition of MoO₂ thin films

Abstract

Molybdenum dioxide (MoO₂), which exhibits both high chemical stability and high electrical conductivity, has been studied for various applications, e.g. as a photocatalyst, an active material for secondary batteries, and the capacitor electrode of dynamic random access memory devices. MoO₂ films are mainly fabricated by vacuum processes, which incur a high manufacturing cost. In this study, we fabricated MoO₂ thin films by mist chemical vapor deposition. Since this method does not require vacuum or a volatile precursor, the processing cost is reduced. Examination of the films deposited at various positions in the furnace at different furnace temperatures revealed that smooth MoO₂ films composed of densely packed crystal grains with a constant thickness of 200 nm can be obtained over a wide area of >30 cm² at a furnace temperature of ~480 °C. The films showed low electrical resistivity of 2 × 10⁻³ Ω cm. Thus, this study provides a low-cost method for the fabrication of MoO₂ thin films.