title: A noncontact thermal microprobe for local thermal conductivity measurement.
abstract: We demonstrate a noncontact thermal microprobe technique for measuring the thermal conductivity κ with ∼3 μm lateral spatial resolution by exploiting quasiballistic air conduction across a 10-100 nm air gap between a joule-heated microprobe and the sample. The thermal conductivity is extracted from the measured effective thermal resistance of the microprobe and the tip-sample thermal contact conductance and radius in the quasiballistic regime determined by calibration on reference samples using a heat transfer model. Our κ values are within 5%-10% of that measured by standard steady-state methods and theoretical predictions for nanostructured bulk and thin film assemblies of pnictogen chalcogenides. Noncontact thermal microprobing demonstrated here mitigates the strong dependence of tip-sample heat transfer on sample surface chemistry and topography inherent in contact methods, and allows the thermal characterization of a wide range of nanomaterials.
authors.affiliation: Department of Mechanical, Aerospace and Nuclear Engineering, Rensselaer Polytechnic Institute, Troy, New York 12180-3590, USA.
authors.forename: Yanliang
authors.initials: Y
authors.lastname: Zhang
authors.forename: Eduardo E
authors.initials: EE
authors.lastname: Castillo
authors.forename: Rutvik J
authors.initials: RJ
authors.lastname: Mehta
authors.forename: Ganpati
authors.initials: G
authors.lastname: Ramanath
authors.forename: Theodorian
authors.initials: T
authors.lastname: Borca-Tasciuc