Electrophysical and thermal properties of NaxCu2-xS (x = 0.05, 0.075, 0.10) and Na0.125Cu1.75S semiconductor alloys

The results of measurements of electronic conductivity and the Seebeck coefficient, as well as X-ray phase analysis, electron microscopy, differential scanning calorimetry (DSC) and studies of the heat capacity of nanocrystalline NaxCu2-xS (x = 0.05, 0.075, 0.10) and Na0.125Cu1.75S semiconducting alloys in the temperature interval of 300 - 600 K are presented. At ambient temperature, the alloys under study consist of three phases: monoclinic Na2Cu4S3, hexagonal Chalcocite Cu2S and rhombohedral digenite Cu9S5. Measurements show that the Seebeck coefficient increases, and the conductivity decreases with increasing sodium concentration in the alloys. Thermal effects near the temperatures of 360 K, 450 K and 640 K have been observed by the DSC method.