The charge transport properties of the low-dimensional thermoelectric materials K2Bi8-xSbxSe13 (02Bi8-xSbxSe13 was analyzed on the basis of the classical semiconductor theory and discussed in the context of recent band calculations. The results suggest that the K2Bi8-xSbxSe13 materials possess coexisting domains with semimetallic and semiconducting characters whose ratio is influenced by the value of x and by local defects. The extent and relative distribution of these domains control the charge transport properties. Electron diffraction experiments performed on samples of K2Bi8-xSbxSe13 with x=1.6 show evidence for such domains by indicating regions with long range ordering of K+/Bi3+ atoms and regions with increased disorder. The semiconducting behavior is enhanced with increasing x (i.e., Sb/Bi ratio) in the composition through a decrease of the semimetallic fraction.
Dyck, Jeffrey S.; Kyratski, T.; Hatzikraniotis, E.; Paraskevopoulos, K. M.; Malliakas, C. D.; Uher, C.; and Kanatzidis, M. G., "Structure inhomogeneities, shallow defects, and charge transport in the series of thermoelectric materials K2Bi8−xSbxSe13" (2006). Physics. 4.