Physics – Condensed Matter – Mesoscale and Nanoscale Physics
Scientific paper
2008-04-02
Phys. Rev. B 78, 115322 (2008)
Physics
Condensed Matter
Mesoscale and Nanoscale Physics
13 pages, 7 figures, 2 tables, typos added, added references for sections 2-4
Scientific paper
10.1103/PhysRevB.78.115322
Electronic structure of bismuth telluride nanowires with the growth directions [110] and [015] is studied in the framework of anisotropic effective mass method using the parabolic band approximation. The components of the electron and hole effective mass tensor for six valleys are calculated for both growth directions. For a square nanowire, in the temperature range from 77 K to 500 K, the dependence of the Seebeck coefficient, the electron thermal and electrical conductivity as well as the figure of merit ZT on the nanowire thickness and on the excess hole concentration are investigated in the constant-relaxation-time approximation. The carrier confinement is shown to play essential role for square nanowires with thickness less than 30 nm. The confinement decreases both the carrier concentration and the thermal conductivity but increases the maximum value of Seebeck coefficient in contrast to the excess holes (impurities). The confinement effect is stronger for the direction [015] than for the direction [110] due to the carrier mass difference for these directions. The carrier confinement increases maximum value of ZT and shifts it towards high temperatures. For the p-type bismuth telluride nanowires with growth direction [110], the maximum value of the figure of merit is equal to 1.3, 1.6, and 2.8, correspondingly, at temperatures 310 K, 390 K, 480 K and the nanowire thicknesses 30 nm, 15 nm, and 7 nm. At the room temperature, the figure of merit equals 1.2, 1.3, and 1.7, respectively.
Bejenari Igor
Kantser Valeriu
No associations
LandOfFree
Thermoelectric properties of the bismuth telluride nanowires in the constant-relaxation-time approximation does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.
If you have personal experience with Thermoelectric properties of the bismuth telluride nanowires in the constant-relaxation-time approximation, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Thermoelectric properties of the bismuth telluride nanowires in the constant-relaxation-time approximation will most certainly appreciate the feedback.
Profile ID: LFWR-SCP-O-389745