Thermoelectric Properties of In-Doped Cu2ZnGeSe4

The impact of a magnetic ion on the thermoelectric properties of copper-rich quaternary selenides

“…Refined unit-cell parameters of the end-member phase Cu 2 ZnGeSe 4 are in good agreement with previous reports [32]. The unit cell volume shows little change (an increase of <0.7%) on replacing iron with zinc, consistent with the similar ionic radii of the Zn 2+ and Fe 2+ cations [33].…”

Understanding the origin of disorder in kesterite-type chalcogenides A2ZnBQ4 (A = Cu, Ag; B = Sn, Ge; Q = S, Se): the influence of inter-layer interactions

“…7,18,19,20 The closely related Cu 2 ZnGeS(Se) 4 phases have also been reported to crystallize in the stannite structure. 4,21,22 Chen et al 23,24 have shown that the most stable configuration of Cu 2 ZnSnS(Se) 4 is the ordered kesterite structure but small energy differences could lead to both the stannite and the disordered configurations being present in experimental samples. 11,12 Whilst materials in the series Cu 2 ZnGeSe 4x S x have been described as crystallizing in the stannite structure, 63 Cu nuclear magnetic resonance (NMR) 25 indicates at least two distinct sites for Cu atoms in Cu 2 ZnGeSe 4 at room temperature, which is inconsistent with the adoption of a structure described in 4 .…”

The onset of copper-ion mobility and the electronic transition in the kesterite Cu2ZnGeSe4

“…12 The introduction of holes results in a significant reduction in electrical resistivity, due to an increase in the charge-carrier concentration. The composition x = 0.075 exhibits the maximum ZT = 0.45 at 670 K. A similar improvement in thermoelectric performance is achieved through the substitution of Ge by In, where the maximum value of ZT = 0.33 is obtained for Cu 2 ZnGe 0.925 In 0.075 Se 4 at 673 K. 22 In both investigations, the temperature dependence of the electrical-transport properties suggests the occurrence of a semiconductor-to-metal transition in the region 450 ≤ T/K ≤ 470. The origin of this transition has not been identified.…”

“…The structural characterization of Cu 2 ZnGeQ 4 (Q = S, Se) in particular has been a contentious issue. While several reports suggest these phases adopt the stannite structure 12,13,21,22 first-principles calculations reveal that both Cu 2 ZnGeS 4 and Cu 2 ZnGeSe 4 compounds are more stable in the kesterite form. 23 Polarized Raman spectroscopy on single crystals 24 suggests that Cu 2 ZnGeSe 4 crystallizes in the kesterite structure, , while Zeier et.…”