Transport properties of β-FeSi₂

Abstract

The aim of this paper is to summarize considerable experimental efforts undertaken within the last decades in the investigations of transport properties of β-FeSi2. The β-FeSi2 compound is the most investigated among a family of semiconducting silicides. This material has received considerable attention as an attractive material for optoelectronic, photonics, photovoltaics and thermoelectric applications. Previous reviews of the transport properties of β-FeSi2 have been given by Lange and Ivanenko et al. about 15 years ago. The Hall effect, the conductivity, the mobility and the magnetoresistance data are presented. Main attention is paid to the discussion of the impurity (defect) band conductivity, the anomalous Hall effect, the scattering mechanisms of charge carriers, as well as to the hopping conduction and the magnetoresistance.

Magnesioreduction Synthesis of Co-Doped β-FeSi2: Mechanism, Microstructure, and Improved Thermoelectric Properties

“…The TE properties of β-FeSi 2 and β-Co 0.07 Fe 0.93 Si 2 synthesized by magnesioreduction and arc-melting were investigated from room temperature up to 773 K. Measurements of the electronic properties were cycled twice and showed good reversibility. Undoped MR β-FeSi 2 samples have elevated electrical resistivity (14 mΩ m) (Figure a) and Seebeck coefficient (550 μV K –1 ) (Figure b) at room temperature which is in agreement with the relatively low charge carrier concentration (10 17 –10 18 cm –3 ) reported for this semiconductor. , Interestingly, the Seebeck coefficients are positive for MR and negative for AM samples indicating n-type and p-type conductions, respectively. Experimental data from the literature report p-type as well as n-type , bulk materials.…”

“…Undoped MR β-FeSi 2 samples have elevated electrical resistivity (14 mΩ m) (g. 10a) and Seebeck coecient (550 µV K −1 ) (g. 10b) at room temperature which is in agreement with the relatively low charge carrier concentration (10 17 -10 18 cm −3 ) reported for this semiconductor. 56,57 Interestingly, the Seebeck coecients are positive for MR and negative for AM samples indicating n-type and p-type conductions, respectively. Experimental data from the literature report ptype 58 as well as n-type 14,27 bulk materials.…”

Optimization of Co additive amount to improve thermoelectric properties of β-FeSi2

“…Among various TE materials, β-FeSi 2 , which has an orthorhombic crystalline structure with a Cmce space group, is considered a potential candidate for high-temperature application due to its environmental friendliness, good thermal stability, strong oxidation resistance, and low cost. [6][7][8][9] However, the ZT of non-doped β-FeSi 2 is still not high enough which limits its application in TE devices. 10,11) The low ZT is because of the decrease in |S| as temperature increases due to the bipolar diffusion effect, and the high ρ due to low carrier concentration (n H ).…”

Doubled Thermoelectric Figure of Merit in p-Type β-FeSi2 via Synergistically Optimizing Electrical and Thermal Transports

“…Among the various kinds of TE materials, β-FeSi 2 has for long been investigated as a promising TE material working at high temperatures. − β-FeSi 2 crystallizes in orthogonal structure with the space group of Cmca . Its optical band gap is around 0.8 eV .…”