Boosted thermoelectric properties of molybdenum oxide thin films deposited on Si substrates

MoO2+ x has novel peculiarities and complexities due to multiple valence states of 4d molybdenum, but high carrier density impedes its thermoelectric (TE) application. Recent investigation has demonstrated that the TE performance of transition metal oxide films can be greatly enhanced by activating a parallel conduction channel in the perovskite substrates through reversible incorporation of oxygen. In this work, we report the TE properties of MoO2 + x thin films deposited on single crystalline Si and quartz glass substrates by magnetron sputtering. The TE power factor (PF) in the former is above 40 times bigger than that in the latter. Such a large enhancement originates mainly from the significantly enhanced Seebeck coefficient, correlated with the contribution of the Si substrate. The highest PF value 1.78 mW/(m.K-2) at 700 K in this MoO2+ x/Si system is comparable to the state-of-the-art in other TE thin films. Based on the preceding research, our experimental results suggest a more economic and scalable route to explore high-performance TE thin films.