Towards More Accurate Determination of the Thermoelectric Properties of Bi(2)Se(3) Epifilms by Suspension via Nanomachining Techniques

We report on the characterization of the thermoelectric properties of Bi(2)Se(3) epifilms. MBE-grown Bi(2)Se(3) films on GaAs (111) A are nanomachined with integrated Pt elements serving as local joule heaters, thermometers, and voltage probes. We suspended a 4 µm × 120 µm Bi(2)Se(3) by nanomachining techniques. Specifically, we selectively etched GaAs buffer/substrate layers by citric acid solution followed by a critical point drying method. We found that the self-heating 3ω method is an appropriate technique for the accurate measurement of the thermal conductivity of suspended Bi(2)Se(3). The measured thermoelectric properties of 200 nm thick Bi(2)Se(3) at room temperature were [Formula: see text] , [Formula: see text] , σ = 75,581 S/m and the figure of merit was [Formula: see text]. The study introduces a method to measure thermal conductivity accurately by suspending thin films.