Strain-field domain structure in Bi2Te3 thermoelectric materials

A strain-field domain structure and a large number of precipitates have been observed in Bi2Te3 n- and p-type thermoelectric materials by transmission electron (TEM) microscopy analysis. The microstructure can be understood as an average unstrained structure plus a sinusoidal strain field. The displacement field of this strain field is generated by dislocations, mostly dipoles that are about 5 nm apart. These domains have a periodicity of 10 nm and lie parallel to the crystallographic (1,0,10) planes. The Burgers-vector of the dislocations within the domains is b=1/2[2,1,w] with w=0.16. These domains might originate from the strain field and motion of precipitates with a size of approximately 2–4 nm, which lie in (−1,0,5) crystallographic planes.