Graduation Year


Document Type




Degree Name

Master of Science (M.S.)

Degree Granting Department


Major Professor

George S. Nolas, Ph.D.

Committee Member

Jacob Gayles, Ph.D.

Committee Member

Dmitri Voronine, Ph.D.


anisotropic transport, chalcogenides, layered materials, XRD rocking curve


Thermoelectric devices provide the means for direct conversion between heat and electricity. The device conversion efficiency, or performance, is directly related to the thermoelectric figure of merit, ZT, of the working materials. Bismuth telluride alloys are the materials currently in use in most thermoelectric devices for near room temperature solid-state refrigeration and power conversion applications. The vast majority of publications in the literature on thermoelectricity report on investigations towards developing new materials with enhanced thermoelectric properties, however Bi2Te3 alloys have been used in thermoelectric devices for decades.

In this thesis, an investigation of crystallographic texturing on large grain polycrystalline n and p-type Bi2Te3 alloys, and the effect of texturing on the transport properties, is discussed. Bi2Te3 is a layered material, and since the arrangement of atoms in the structure leads to strong anisotropy the role of texturing continues to be of primary importance for optimum device performance using these materials. Texturing both parallel and perpendicular to the growth direction of polycrystalline n and p-type Bi2Te3 alloys synthesized from the melt will be described. The texture-thermoelectric property relationships are described in detail. These materials are highly textured with superior thermoelectric properties compared to similar polycrystalline materials with randomly oriented grains.