Constituent Element Addition to n-Type Bi2Te2.67Se0.33 Thermoelectric Semiconductor without Harmful Dopants by Mechanical Alloying

摘要

N-type Bi2Te2.67Se0.33 thermoelectric materials with added constituent elements were prepared without the addition of harmful dopants using mechanical alloying (MA) followed by hot pressing (HP). All the prepared samples were identified from the Bi2Te3-Bi2Se3 solid-solution diffraction peak. They were all single-phase n-type semiconductors. The maximum dimensionless figures of merit, ZT, of Bi2Te2.67(Se-0.33)(1+0.06), Bi-2(Te-2.67)(1+0.06)Se-0.33, and Bi-2(Te2.67Se0.33)(1+0.03) were 0.93 at 440 K, 0.99 at 441 K, and 0.97 at 442 K, respectively. These results indicate that the figure of merit of Bi2Te2.67Se0.33 doped with constituent elements, prepared using the MA-HP process, is nearly same as the highest value, i.e., 1.0, reported in the literature.