High room-temperature figure of merit of thin layers prepared by laser ablation from Bi2Te3 target

Abstract

The figure of merit ZT is measured by a Harman method on simple devices prepared on single thermoelectric layers of different thicknesses. The thermoelectric layers are prepared at different conditions by laser ablation from Bi2Te3 target. The best measured figure of merit ZT is for our devices ZT=2.65. This result is comparable with the results obtained on superlattices. ZT oscillated with the thickness of the layers. On some devices the Seebeck coefficient is measured and using conductivity measurements along the thermoelectric layers the thermal conductivity is estimated from ZT. The low thermal conductivity of samples is explained by the quantum size effect and by existence of few phases of type Bi2(m+n)Te3n in the thermoelectric layers.

Growth and transport properties of oriented bismuth telluride films

“…The greatly improved ZT value to 2.4 was first reported in Bi 2 Te 3 /Sb 2 Te 3 superlattice thin film by Venkatasubramanian et al [10]. Another high ZT value of 2.65 was obtained in Bi 2 Te 3 film fabricated by pulsed laser deposition (PLD) [11].…”

“…The ZT value can be significantly improved in low-dimensional materials owing to the effect of quantum confinement of charge carriers and phonon scattering at the boundaries and interfaces [5,6]. Several materials with special nanostructures, such as nanoplates, film, nanotubes and nanowires, have been synthesized in recently years, which show promising thermoelectric properties [7][8][9][10][11]. The greatly improved ZT value to 2.4 was first reported in Bi 2 Te 3 /Sb 2 Te 3 superlattice thin film by Venkatasubramanian et al [10].…”

Thermoelectric properties of Bi–Te films with controlled structure and morphology

“…Walachova et al 17 and Zeipl et al 18 obtained ␣ in the range from −20 V / K to −80 V / K and ϳ 0.2-0.5 m⍀ cm starting from a stoichiometric Bi 2 Te 3 target.…”

Fabrication and characterization of Bi0.4Te3.0Sb1.6 thin films by flash evaporation method

“…There are presently many deposition methods such as flash evaporation [6][7][8], co-sputtering [9,10], pulsed laser deposition [11,12], metal organic chemical vapor deposition (MOCVD) [13,14] and molecular beam epitaxy (MBE) [15][16][17]. Thus, although there are many deposition methods, the resulting devices are not yet appropriate for commercial viability because of higher production costs due to expensive equipments, and/or inadequate thin film properties.…”