Sumitomo Special Metals Co., Ltd.

Nobuhiro Sadatomi

Osamu Yamashita

Tsunekazu Saigo

Masao Noumi

Shunichi Haruyama

A thermoelectric conversion material is formed of a polycrystal structure of crystal grains composed of a silicon-rich phase, and an added element-rich phase in which at least one type of added element is deposited at the grain boundary thereof, the result of which is an extremely large Seebeck coefficient and low thermal conductivity, allowing the thermoelectric conversion rate to be raised dramatically, and affording a silicon-based thermoelectric conversion material composed chiefly of silicon, which is an abundant resource, and which causes extremely low environmental pollution.

Thermoelectric conversion material and method of producing the same

A silicon-based polycrystal powder, which contains no more than 30 at % Ge, C, Sn, or another such element that does not generate carriers as well as an added element that does generate carriers, and which has a crystal structure including crystal grains made up of at least 80 at % silicon, and a grain boundary phase where at least one type of said added element is precipitated at the boundary of said crystal grains, is mixed with a clathrate compound powder with low thermal conductivity and electrical resistivity, and this mixture is subjected to hot compression molding, the product of which has a composite structure in which the particles of the clathrate compound polycrystals are disposed around the particles of the silicon-based polycrystals.

Thermoelectric conversion material, and method for manufacturing same

A silicon based conductive material based on a semiconductor silicon and having an electric resistivity of 10 (&OHgr;&middot;m) or less at ambient temperature which has been unattainable heretofore, while facilitating production and handling. An electric resistivity of 10 (&OHgr;&middot;m) or less, which is common for conductors can be realized by adding relatively large quantities of various kinds of elements to silicon. The conductive material can be provided in a semiconductor silicon substrate in a desired pattern by ion beam implantation and patterning. It can be employed not only in the form of a substrate, a rod or a wire, but also in the form of fine particles dispersed in a resin or glass to be employed in various applications requiring conduction, including a conductive sheet material.

Silicon based conductive material and process for production thereof

With the thermo-electric conversion element according to the present invention, the power generating efficiency (in other words, the conversion efficiency) can be improved by inserting as metallic film made of either Ag, Al, or silver soldering material for the PN junction formation between the Si based P type and N type semiconductors and inserting a metallic film made of either Zn, Ni, Cu, Ag, Au, or Cu-30Zn at a connecting portion between the semiconductors and lead wires, so that the electromotive power and the thermo-electromotive force are not cancelled each other due to the Schottky barrier which is generated at the interfacial area between the metals and semiconductors. The desired thermo-electric conversion efficiency can be achieved by the material presented in this invention without any deterioration of the original thermo-electric properties.

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Ibaraki, Japan

Nobuhiro Sadatomi