Enhanced Thermoelectric Properties of Silicon via Nanostructuring

Abstract

The effectiveness of thermoelectric (TE) materials at converting heat gradients into electricity, and vice versa, is quantified by the dimensionless figure of merit, ZT. Current TE materials, such as Bi 2 Te 3 and PbTe, have ZT values of approximately 1, but contain highly toxic and/or rare elements, which limits their widespread use. However, Si is a non-toxic, inexpensive, and abundant element. Even though bulk Si exhibits good electrical properties, its lattice thermal conductivity (¬ lat ) is high (>100 Wm ¹1 K ¹1), which results in a ZT value of approximately 0.01 at room temperature. If it were possible to lower the ¬ lat of Si without altering the electrical properties, Si would be an ideal TE material. These changes can be realized by nanostructuring Si. In this review, we discuss the recent achievements in the enhancement of the TE properties of Si via nanostructuring. Based on these recent results, we also indicate some potential topics to investigate to enhance the TE properties of Si further.

The effect of YSi2 nanoinclusion on the thermoelectric properties of p‐type SiGe alloy

“…Theoretical calculations showed that silicide nanoparticles could suppress lattice thermal conductivity ( κ l ) effectively and enhanced ZT by several folds . Experimentally, a number TE studies of silicide nanoparticles in SiGe or Si matrix have been demonstrated, for example, FeSi 2 , MgSi 2 , WSi 2 , CrSi 2 , MoSi 2 , NiSi 2 , and VSi 2 . However, some experiments showed that even though the thermal conductivity were decreased, the ZT of such systems were not enhanced , which was due to the changes in S and σ when silicide nanoinclusions were introduced.…”

A review on Silicide based materials for thermoelectric applications

“…The observed peak positions are similar with that of Mo5Si3. N-type Si nanoparticles were used to fabricate mass Si nanocrystal by sintering process by K. Kurosaki, et al [59]. The thermoelectric properties of mass silicon were presented.…”

Si-Based Materials for Thermoelectric Applications

“…In recent years, significant improvements in zT in various traditional TE materials have been achieved, particularly via considerable methods for the minimization of κ lat including alloy scattering [13,14], rattling [15,16], lone-pair electrons [17,18], and nanostructuring [19,20,21,22,23,24,25,26]. Nanostructuring permits κ lat reduction while maintaining high electrical properties [19,20,21,22,23,24,25,26]. In addition to Si, many metal silicides are considered advanced TE materials because of their low toxicities and high chemical stabilities.…”