N-TYPE BORON-CARBON BASED ALLOYS

P-TYPE BORON-CARBON (B-C) ALLOYS OVER THE SINGLE-PHASE REGION B9C TO B4C EXHIBIT VERY UNUSUAL SEMICONDUCTOR PROPERTIES. FOR EXAMPLE, BOTH THE SEEBECK COEFFICIENT AND ELECTRICAL CONDUCTIVITY INCREASE WITH TEMPERATURE, MAKING THESE ALLOYS ATTRACTIVE FOR THERMOELECTRIC ENERGY CONVERSION. IT APPEARS THAT B-C ALLOYS DO NOT EXHIBIT A MAXIMUM IN FIGURE-OF-MERIT (Z) WITH INCREASING TEMPERATURE. SINCE THE HIGHEST REPORTED Z OF B-C ALLOYS AT 1,000 DEGREES CENTIGRADE IS 0.85 X 10(-3) DEGREES CENTIGRADE, THERE IS REASON TO BELIEVE A Z OF >1.2 X 10(-3) AT 1,200 DEGREES CENTIGRADE IS ACHIEVABLE. MANY LABORATORIES ARE ACTIVELY WORKING ON B-C AND OTHER ALLOYS. IT IS EXPECTED THAT THESE P-TYPE ALLOYS WILL BE IMPROVED FURTHER IN THEIR Z VALUES. THIS PROGRAM SEEKS TO DEVELOP THE COMPANION N-TYPE MATERIAL BASED ON B-C ALLOYS. PRESENTLY, NO VIABLE CANDIDATES WITH ASIMILAR THERMAL EXPANSION AND EQUIVALENT THERMAL STABILITY ARE KNOWN. BASED ON PRIOR STUDIES OF B-C ALLOYS WITH A VARIETY OF ADDITIVES, A MODEL HAS BEEN DEVELOPED THAT INDICATES WHICH B-C BASED COMPOSITIONS SHOULD BE PURSUED. P-TYPE B-C, AS WELL AS OTHER POTENTIAL BORIDES (B12A1, GDB66, B12AS, B13P2, ETC.), ARE EXPECTED TO BENEFIT FROM THIS WORK.