Perpustakaan Digital ITB

ZnO is a direct band gap material that hasnumerous optoelectronic applications. Recently, the thermo-electric behavior of ZnO has drawn much attention because itis expected to enrich the multifunctional application of ZnO.However, the high thermal conductivity nature of ZnO (?50W/(m·K)) is a challenge to further increase its thermoelectrticfigure of merit (ZT). In this paper, a way to increase theZTofZnO thinfilms by insertion of silicon-rich oxide (SRO)interlayers is reported. All of the constituents are earth-abundant and environmental friendly. The effects of thenumber of SRO layers, thickness, grain size, heat treatment, and crystallinity of ZnO of the superlattices on the thermoelectricbehaviors of ZnO were investigated. The thermoelectricZTwas determined by the transient Harman method by measuring theSeebeck voltage. The thermal conductivity of the ZnO/SRO superlattices that is crucial to elucidate theZTbehaviors iscalculated using molecular dynamic simulation, in which the Zn?O and Zn?Zn interactions were described by the Born?Mayer potential and the short-range non-Coulombic O?O interaction was described by the Morse potential. For a given totalZnO/SRO thickness, the grain size of the ZnO decreases monotonically with the increasing number of SRO layers, thus leadingto a decrease of the thermal conductivity and an increase of theZTof the superlattices. As the best result, the annealed 45 nmthick ZnO thinfilm with three SRO interlayers presents a highZTof?0.16 at room temperature. A comprehensive study onthe ZnO/SRO superlattice-based thermoelectrtic devices was carried out by the experiment and theoretical simulation. Theresults imply potential thermoelectric application of the ZnO/SRO superlattices