| 초록 |
Binary chalcogenide, SnSe has recently risen as a novel material for the thermoelectric applications. Because intrinsic low thermal conductivity of SnSe originating from the anisotropic bonding between Sn and Se, it achieved the world’s highest figure of merit, which is 2.6 at 923K in 2014. However, this performance is achieved from the single crystal bulk SnSe. Despite active research have been progressed on polycrystalline bulk SnSe thermoelectric devices, the figure of merit remains around 1 because of lower electrical conductivity than single crystal SnSe. To overcome the limitation of polycrystalline SnSe thermoelectric device, we tried to measure the thermoelectric properties of polycrystalline SnSe as thin films state. In thin films state, surface properties of material are dominant over the bulk properties. Therefore, we deduce that scattering of phonon by surface impurities or dislocation can be enhanced and it results the decrease of thermal conductivity of the film. Here, we prepared thin film polycrystalline SnSe by thermal co-evaporation using an elemental Sn source and a Se thermal cracker. Thermoelectric properties of prepared thin films such as electrical conductivity, Seebeck coefficient, thermal conductivity depend on temperature were measured. And we also observed the enhancement of thermoelectric properties of the stoichiometry controlled SnSe thin films. Details of the film preparation process as well as thermoelectric properties of polycrystalline SnSe thin films will be discussed |
