Thermal conductivity of mechanically joined semiconducting/metal nanomembrane superlattices

Daniel Grimm, Richard B. Wilson, Bezuayehu Teshome, Sandeep Gorantla, Mark H. Rümmeli, Thomas Bublat, Eugenio Zallo, Guodong Li, David G. Cahill, Oliver G. Schmidt

Research output: Contribution to journalArticle

Abstract

The decrease of thermal conductivity is crucial for the development of efficient thermal energy converters. Systems composed of a periodic set of very thin layers show among the smallest thermal conductivities reported to-date. Here, we fabricate in an unconventional but straightforward way hybrid superlattices consisting of a large number of nanomembranes mechanically stacked on top of each other. The superlattices can consist of an arbitrary composition of n- or p-type doped single-crystalline semiconductors and a polycrystalline metal layer. These hybrid multilayered systems are fabricated by taking advantage of the self-rolling technique. First, differentially strained nanomembranes are rolled into three-dimensional microtubes with multiple windings. By applying vertical pressure, the tubes are then compressed and converted into a planar hybrid superlattice. The thermal measurements show a substantial reduction of the cross-sectional heat transport through the nanomembrane superlattice compared to a single nanomembrane layer. Time-domain thermoreflectance measurements yield thermal conductivity values below 2 W m-1 K-1. Compared to bulk values, this represents a reduction of 2 orders of magnitude by the incorporation of the mechanically joined interfaces. The scanning thermal atomic force microscopy measurements support the observation of reduced thermal transport on top of the superlattices. In addition, small defects with a spatial resolution of ∼100 nm can be resolved in the thermal maps. The low thermal conductivity reveals the potential of this approach to fabricate miniaturized on-chip solutions for energy harvesters in, e.g., microautonomous systems.

Original languageEnglish (US)
Pages (from-to)2387-2393
Number of pages7
JournalNano letters
Volume14
Issue number5
DOIs
StatePublished - May 14 2014

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Keywords

  • GaAs
  • rolled-up nanotechnology
  • scanning thermal AFM
  • SiGe
  • superlattice
  • Thermal conductivity
  • time-domain thermoreflectance

ASJC Scopus subject areas

  • Condensed Matter Physics
  • Bioengineering
  • Chemistry(all)
  • Materials Science(all)
  • Mechanical Engineering

Cite this

Grimm, D., Wilson, R. B., Teshome, B., Gorantla, S., Rümmeli, M. H., Bublat, T., Zallo, E., Li, G., Cahill, D. G., & Schmidt, O. G. (2014). Thermal conductivity of mechanically joined semiconducting/metal nanomembrane superlattices. Nano letters, 14(5), 2387-2393. https://doi.org/10.1021/nl404827j