Concentration‐dependent excess Cu doping behavior and influence on thermoelectric properties in Bi ₂ Te ₃

Abstract

Excess Cu has been reported as an effective way to enhance the thermoelectric performance of n-type Bi 2 Te 3 -based alloys as well as to secure the reproducibility of their electronic properties. However, the effect of Cu doping into Bi 2 Te 3

Comparison of influence of intercalation and substitution of Cu on electrical and thermoelectric transport properties of InSe alloys

“…This indicates that the Cu 0 atom intercalated into the layer behaves as an electron donor and leads to an increase in the carrier concentration. 19–22 Group XI elements, such as Cu and Ag, are utilized as electron donors during their intercalation into van der Waals layered materials, primarily due to their distinctive electron configurations (Cu: 4s 1 3d 10 ). Cu, for instance, exhibits a tendency to release an electron in pursuit of attaining a stable, closed-shell electron configuration.…”

“…Cu is often used as an n-type dopant in layered metal chalcogenides, particularly when Cu atoms are intercalated into the layer. 19–22 Sun et al added Cu to layered Bi 2 Se 3 alloys, and the power factor of all Bi 2 Se 3 samples with added Cu was enhanced due to increased electrical conductivity. 19 You et al investigated the influence of dynamic doping of interstitial Cu on the electrical properties of n-type PbTe.…”

“…For example, in Bi 2 Se 3 and Bi 2 Te 3 systems, Cu can behave as an acceptor or a donor depending on its location in the lattice. Cu acts as a donor when intercalated into van der Waals gaps, 19–22 while it acts as an acceptor substituted into Bi sites in Bi 2 Te 3 . 23–25…”