Submitted on October 19, 2006
Accepted on December 4, 2006
Ultralow Thermal Conductivity in Disordered, Layered WSe2 Crystals
Catalin Chiritescu 1,
David G. Cahill 1*,
Ngoc Nguyen 2,
David Johnson 2,
Arun Bodapati 3,
Pawel Keblinski 3,
Paul Zschack 4
1 Department of Materials Science and Engineering, Frederick Seitz Materials Research Laboratory, University of Illinois, Urbana, IL 61801, USA.
2 Department of Chemistry, University of Oregon, Eugene, OR 97403, USA.
3 Department of Materials Science and Engineering, Rensselaer Polytechnic Institute, Troy, NY 12180, USA.
4 Advanced Photon Source, Argonne National Laboratory, Argonne, IL 60439, USA.
* To whom correspondence should be addressed.
David G. Cahill , E-mail: d-cahill{at}uiuc.edu
The cross-plane thermal conductivity of thin films of WSe2, grown from alternating W and Se layers, is as small as 0.05 watts per meter per Kelvin at room temperature, 30 times smaller than the c-axis thermal conductivity of single-crystal WSe2 and a factor of 6 smaller than the predicted minimum thermal conductivity for this material. We attribute the ultralow thermal conductivity of these disordered, layered crystals to the localization of lattice vibrations induced by the random stacking of two-dimensional crystalline WSe2 sheets. Disordering of the layered structure by ion bombardment increases the thermal conductivity.
