Thermal Stability, Optical and Electrical Properties of Substoichiometric Molybdenum Oxide

Substoichiometric molybdenum oxide ceramics have aroused widespread interest owing to their promising optical and electrical performance. In this work, the thermal stability and decomposition mechanism of Mo₉O₂₆ and Mo₄O₁₁ at 700-1000 °C and 700-1100 °C were investigated, respectively. Based on this information, MoO_x (2 < x < 3) bulk ceramics were prepared by spark plasma sintering (SPS). The results show that Mo₉O₂₆ is stable up to 790 °C in an argon atmosphere. As the temperature rises, it decomposes into Mo₄O₁₁. Mo₄O₁₁ can exist stably at 830 °C, beyond which it will convert to MoO₂. The MoO_x ceramic bulks with four different components (MoO_2.9, MoO_2.8, MoO_2.7 and MoO_2.6) were successfully sintered by SPS, and their relative density was greater than 96.4% as measured by the Archimedes principle. The reflectivity of MoO_x ceramic bulk is low and only 6.3% when the composition is MoO_2.8. The resistivity increases from 10^-3 to 10^-1 Ωcm with the increase in the O/Mo atomic ratio x. In general, the thermal stability information provides a theoretical basis for the processing of MoO_x materials, such as the sintering of the MoO_x target. The optical and electrical properties show that MoO_x is a low-reflective conductive oxide material with great photoelectric application value.