ith Se due to the higher lattice disorder (Figure 8d).After having subtracted the electronic contribution κe, κdecreased with temperature in the low-temperature range andstabilized or increased at higher temperatures, when the bipolarcontribution, κbi, became significant (Figure 9e). Above theDebye temperature, ca. 145 K for Bi2Te3,49 phonon scattering byUmklapp mechanism leads to a T−1 dependence of the latticethermal conductivity, κL. On the other hand, κbi displays anexponential dependence with temperature and the material bandgap,After having subtracted the electronic contribution κe, κdecreased with temperature in the low-temperature range andstabilized or increased at higher temperatures, when the bipolarcontribution, κbi, became significant (Figure 9e). Above theDebye temperature, ca. 145 K for Bi2Te3,49 phonon scattering byUmklapp mechanism leads to a T−1 dependence of the latticethermal conductivity, κL. On the other hand, κbi displays anexponential dependence with temperature and the material bandgap,