Thermal and electrical conductivity of single crystalline kesterite Cu2ZnSnS4

For single crystalline sulfur based kesterite Cu2ZnSnS4 the electrical and thermal conductivity are measured from 20 K to 320 K. The electrical conductivity decreases exponentially with decreasing temperature. The temperature dependence can be assigned to Mott variable range hopping, an electrical transport process within an impurity band in the band gap. With the 3 amp; 969; method a thermal conductivity room temperature value of 5.1 0.5 Wm amp; 8722;1K amp; 8722;1 and a maximal value of 8.0 0.5 Wm amp; 8722;1K amp; 8722;1 at 100 K are found. Phonon phonon umklapp scattering can explain the high temperature range from 100 K to 320 K. The low temperature values of the thermal conductivity are dominated by the temperature dependence of the specific heat capacity, due to a reduced phonon mean free path, owing to phonon impurity scatterin