Accession Number:

AD0291739

Title:

SINGLE CRYSTAL BISMUTH TELLURIDE

Descriptive Note:

Corporate Author:

AIR FORCE CAMBRIDGE RESEARCH LABS L G HANSCOM FIELD MASS

Personal Author(s):

Report Date:

1962-09-01

Pagination or Media Count:

36.0

Abstract:

Bismuth telluride single crystals were grown by the Czochralski pulling method in a furnace similar to that used by Ainsworth. Bismuth rich and stoichiometric melts led to p-type crystals. Large excesses of Te and doping with Cu2Te led to n-type crystals. Single crystal gwowth was sustained at rates as high as 8.5 cmhr from p-type melts and 0.5 cmhr from n-type melts. Growth rates above 3 cmhr resulted in rectangular cross sections. Those below 1 cmhr resulted in elliptical cross sections similar to those reported by Ainsworth. Typical cross section dimensions were 1.5 x 0.5 cm. Single crystals have been grown up to 22 cm in length. The variation of thermoelectric power with melt composition was observed for compositions near stoichiometry. Normal p-type thermoelectric powers seebeck coefficient ranged from 220 to 260 microvoltsdeg C. Normal n-type thermoelectric powers of -15 to -250 microvoltsdeg C were obtained. X-ray diffraction lines observed agree with the ASTM index to within experimental error. A transmission edge was observed at approximately 0.145 ev. Author

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Distribution Statement:

APPROVED FOR PUBLIC RELEASE