Thermoelectric properties of electrically gated bismuth telluride nanowires

Abstract

We theoretically studied the effect of the perpendicular electric field on the thermoelectric properties of the intrinsic, n−type and p−type bismuth telluride nanowires with the growth direction [110]. The electronic structure and the wave functions were calculated by solving self-consistently the system of the Schrödinger and Poisson equations using the spectral method. The Poisson equation was solved in terms of the Newton -Raphson method within the predictor-corrector approach. The electron -electron exchange -correlation interactions were taken into account in our analysis. In the temperature range from 77 to 500 K, the dependences of the Seebeck coefficient, thermal conductivity, electron (hole) concentration, and thermoelectric figure of merit on the nanowire thickness, gate voltage, and excess hole (electron) concentration were investigated in the constant relaxation-time approximation. The results of our calculations indicate that the external perpendicular electric field can increase the Seebeck coefficient of the bismuth telluride nanowires with thicknesses of 7 -15 nm by nearly a factor of 2 and enhance ZT by an order of magnitude. At room temperature, ZT can reach a value as high as 3.4 under the action of the external perpendicular electric field for realistic widths of the nanowires. The obtain results may open up a completely new way for a drastic enhancement of the thermoelectric figure of merit in a wide temperature range.

Growth and surface potential characterization of Bi2Te3 nanoplates

“…[1][2][3] Recently both theoretical predictions and experimental investigations have demonstrated that Bi 2 Te 3 is also a topological insulator (TI). [4][5][6] TI is a new state of quantum matter with an insulating bulk gap or gapless edge and current-carrying massless Dirac surface states, and exhibits a rich variety of physical phenomena such as anomalous magneto-electric coupling and Majorana excitations.…”

“…Electronic mail: jxzhong@xtu.edu.cn (J. X. Zhong), xqi@xtu.edu.cn (X. Qi). 3 ) are placed at the heating zone. Before the experiment, the quartz tube is initially pumped down to 33 Torr and flushed several times with Ar gas to remove oxygen residue.…”

Thermoelectric properties of Bi2Te3 atomic quintuple thin films

“…The existing theoretical studies on the thermoelectric devices are mostly based on either the continuum models [11,12,[16][17][18] or the tight-binding methods. [19,20] Continuum models (effective mass approximation) though useful for their simplicity and computational efficiency, cannot capture the details of the atomistic effects that can be present in lowdimensional structures.…”

Enhanced thermoelectric performance in n -type Bi 2 Te 2.95 Se 0.05 bulks fabricated by high pressure sintering technique

“…Compared to other existing fabrication methods, the samples prepared by high pressure sintering method have the following advantages: higher efficiency, lower cost, more suitable for large-scale production, more homogeneous nanocrystalline grain and restraining grain from coarsening during sintering process, etc. In addition, pressure tuning is thought to be one of the ways to improve the TE properties of thermoelectric materials [31]. In our previous research, we prepared Bi 0.5 Sb 1.5 Te 2.7 Se 0.3 bulk samples through high pressure sintering technique together with heat treatment, and found ZT value to increase up to 1.16 at 323 K [30].…”