Antimony as an amphoteric dopant in lead telluride

TitleAntimony as an amphoteric dopant in lead telluride
Publication TypeJournal Article
Year of Publication2009
AuthorsJaworski CM, Tobola J, Levin EM, Schmidt-Rohr K, Heremans JP
Journal TitlePhysical Review B
Date Published09/01
ISBN Number1098-0121
Accession NumberISI:000270383300064
Keywordsalloys, chalcogenides, density-of-states, electronic-structure, pbse, pbte

We elucidate the amphoteric nature of antimony as a dopant in PbTe. Band-structure calculations show that Sb substituting for Pb is a donor and that Sb on the Te site is an acceptor giving rise to a large excess density of states (DOS). Experimentally, in Te-rich Pb1-xSbxTe samples, Te-125 NMR spectroscopy shows that Sb substitutes for Pb and transport data reveal that it then acts as a simple donor. In Pb-rich PbSbxTe1-x samples, Te-125 NMR shows that little Sb substitutes for Te when samples are prepared above 770 K and then quenched; Pb-207 NMR shows four types of charge carriers, but only a majority hole and a minority electron contribute to transport. Sb acts as an acceptor in PbSbxTe1-x, but the large DOS calculated must correspond to a large concentration of localized holes and the Seebeck coefficient is not enhanced.

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