Hirohide Ishiguro

Fabrication of Bi2-xSbxTe3 (x=0-1.5) Thick Film by Centrifugal Deposition

A Bi2-xSbxTe3(x=0-1.5) thick film thermoelectric element was fabricated using centrifugal deposition and its Sb content-dependent thermoelectric properties were investigated. When the Sb content was low (x=0.5), two types of fine structure along the direction of the thickness were observed. Pole figure measurements revealed that the vicinity of the film surface was composed of single crystal layers oriented along the c-axis and the vicinity of the interface with the substrate was composed of randomly orientated layers. As the content of Sb increased, the degree of orientation improved, and at x=1.5 the entire film was close to a single crystal. A Bi0.5Sb1.5Te3 thick film showed p-type thermoelectric properties and a thermoelectric power factor of 3.5 ×10-3W/mK2. It was thus demonstrated that centrifugal deposition can be used to fabricate thermoelectric elements with high efficiency.

Centrifugal Sintering - Development of a New Pressure Sintering Process -

Centrifugal sintering is a novel process for the preparation of thick films. In this process, high gravity such as 104g is applied at high temperatures. Because of the distinctive measure of pressing by the centrifugal force, gradient of pressure arises in the specimen, resulting in the graded porous structure during the progress of sintering. After the sintering, highly densified thick films are obtained. Furthermore, crack formation was suppressed by this process.