Scanning thermoelectric microscopy of local thermoelectric behaviors in (Bi,Sb)2Te3 films

In this paper we develop scanning thermoelectric microscopy (STeM) on the basis of commercial atomic force microscope. The nanoscale thermoelectric behaviors of (Bi,Sb)2Te3 (BST) thin films were studied. 3ω-technique was used for thermal conductivity imaging and quantitative thermal characterization. By acquiring the unique Seebeck information from 2ω frequency component, nanoscale thermoelectric images were firstly obtained, exhibiting remarkably inhomogeneous distribution of local Seebeck coefficient in the thin films. Positive thermoelectric response is revealed by the modulation of temperature difference between thermal tip and sample, corresponding to p-type conduction within BST sample.