Structure of layered WSe2 thin films with ultralow thermal conductivity

Crystallographic ordering and defects in WSe(2) thin films with ultralow thermal conductivity are characterized by electron imaging and diffraction in cross-sectional geometry. The results show that the film consists of oriented, coherent crystallites that are a few nanometers in diameter. Two films of different thickness with different thermal conductivity are compared. We show that the film with a lower thermal conductivity is characterized by less coherent crystallites with a greater degree of misorientation.