title: Conductive scanning probe microscopy of nanostructured Bi2Te3.
abstract: In order to explain the unique thermoelectric properties of bulk nanocomposite p-type bismuth antimony telluride, its structural and electrical properties are investigated using transmission electron microscopy (TEM) and atomic force microscopy with a conductive probe (C-AFM). The material is observed to contain both nano- and micro-sized grains with sizes varying from 10 nm to 3 µm. This unique structure promotes phonon scattering, thereby decreasing the thermal conductivity to below 1 W mK(-1) at room temperature. Moreover, the C-AFM data show that the electrical conductivity of nanosized grains is higher than the bulk value and reaches 1600 S cm(-1). This results in a moderate increment of the overall electrical conductivity, thereby increasing the figure of merit (ZT) up to 1.4 at 100 °C. In addition to demonstrating a powerful scanning probe microscopy (SPM) based investigation technique that requires minimal sample preparation, our findings contribute towards better understanding of the enhancement of thermoelectric properties of nanocomposite thermoelectric materials.
authors.affiliation: Laboratory of Energy and Nanosciences, Masdar Institute of Science and Technology, Abu Dhabi, UAE.
authors.forename: Tewfik
authors.initials: T
authors.lastname: Souier
authors.forename: Guang
authors.initials: G
authors.lastname: Li
authors.forename: Sergio
authors.initials: S
authors.lastname: Santos
authors.forename: Marco
authors.initials: M
authors.lastname: Stefancich
authors.forename: Matteo
authors.initials: M
authors.lastname: Chiesa
mesh_terms: D001729:Bismuth / Q000737:chemistry*; D004553:Electric Conductivity; D046911:Macromolecular Substances / Q000737:chemistry; D008422:Materials Testing / Q000379:methods; D020527:Microscopy, Scanning Probe / Q000379:methods*; D008968:Molecular Conformation; D049329:Nanostructures / Q000737:chemistry* / Q000648:ultrastructure*; D010316:Particle Size; D013499:Surface Properties; D013691:Tellurium / Q000737:chemistry*; D013814:Thermal Conductivity
chemical_list: D046911:Macromolecular Substances; C542787:bismuth telluride; D013691:Tellurium; D001729:Bismuth