Method for Producting a Thermoelectric Material

Abstract

A thermoelectric material to exploit a unidirectional thermal gradient for the production of electrical power, comprising a body fabricated from milled silicon alloyed with a dopant and sintered at a temperature below the melting point of silicon.

What is claimed is: 
     
         1 . A process for fabricating a thermoelectric material, comprising:
 admixing a quantity of silicon metal particulates with a liquid having the ability to limit oxidation of the silicon metal particulates, said step of admixing maintained for a time sufficient for wetting the first quantity of silicon metal particulates in the liquid prior to attrition to develop an oxidant free mixture of particulates and liquid;   introducing said oxidant-free mixture of particulates and liquid into an attrition mill, said step of introducing proceeding in the absence of oxidants;   subjecting said silicon metal particulates of said mixture to attrition in the attrition mill for a time sufficient to reduce at least a portion of said silicon metal particulates to a preselected average particle size, said liquid limiting oxidation of said silicon metal particulates during said time, to produce a second quantity of reduced particle size silicon metal particulates being essentially oxidant free;   withdrawing from said attrition mill at least a portion of said second quantity of reduced particle size silicon metal particulates, along with a portion of said liquid,   mixing the silicon metal particulates with a dopant to form a thermoelectric material; and   sintering the milled silicon metal particulates and dopant at a temperature below the melting point of silicon.   
     
     
         2 . The process of  claim 1  wherein the dopant is a material selected in order to make the thermoelectric material an n-type semiconductor. 
     
     
         3 . The process of  claim 1  wherein the dopant is a material selected in order to make the thermoelectric material a p-type semiconductor. 
     
     
         4 . The process of  claim 1  wherein the dopant is arsenic. 
     
     
         5 . The process of  claim 1  wherein the thermoelectric material includes two sides, wherein a first side is an n-type semiconductor and a second side is a p-type semiconductor. 
     
     
         6 . The process of  claim 1  wherein the preselected average particle size is less than 1,000 nanometers. 
     
     
         7 . The process of  claim 1  wherein the preselected average particle size is less than 600 nanometers. 
     
     
         8 . The process of  claim 1  wherein the preselected average particle size is less than 300 nanometers. 
     
     
         9 . A method for fabricating a thermoelectric material, comprising:
 providing an initial feedstock of silicon metal particulates;   providing an extracting liquid to extract oxidants from the silicon metal particulates;   combining the silicon metal particulates and the extracting liquid into a mixture and milling said mixture;   withdrawing at least a portion of the milled mixture;   within the withdrawn portion of the milled mixture, separating milled silicon metal particulates from the extracting liquid; and   mixing the milled silicon metal particulates with a dopant to form a thermoelectric material.   
     
     
         10 . The method of  claim 9  further comprising the step, following mixing the milled silicon metal particulates with a dopant, of sintering the milled silicon metal particulates and dopant at a temperature below the melting point of silicon. 
     
     
         11 . The method of  claim 9  wherein the dopant is a material selected in order to make the thermoelectric material an n-type semiconductor. 
     
     
         12 . The method of  claim 9  wherein the dopant is a material selected in order to make the thermoelectric material a p-type semiconductor. 
     
     
         13 . The method of  claim 9  wherein the thermoelectric material includes two sides, wherein a first side is an n-type semiconductor and a second side is a p-type semiconductor. 
     
     
         14 . A thermoelectric material to exploit a unidirectional thermal gradient for the production of electrical power, comprising: a body fabricated from milled silicon alloyed with a dopant and sintered at a temperature below the melting point of silicon. 
     
     
         15 . The thermoelectric material of  claim 14  wherein the dopant is a material selected in order to make the thermoelectric material an n-type semiconductor. 
     
     
         16 . The thermoelectric material of  claim 14  wherein the dopant is a material selected in order to make the thermoelectric material a p-type semiconductor. 
     
     
         17 . The thermoelectric material of  claim 14  wherein the body includes two sides, a first side being an n-type semiconductor and a second side being a p-type semiconductor. 
     
     
         18 . The thermoelectric material of  claim 14  wherein the milled silicon comprises particles with an average particle size of less than 1,000 nanometers. 
     
     
         19 . The thermoelectric material of  claim 14  wherein the milled silicon comprises particles with an average particle size of less than 600 nanometers. 
     
     
         20 . The thermoelectric material of  claim 14  wherein the milled silicon comprises particles with an average particle size of less than 300 nanometers.