engleski

Low-temperature transport properties in Cu2Se

Widespread application of thermoelectric technologies requires the development of low- cost high efficiency materials. Transition metal chalcogenides (TMC) are interesting in this regard. As an important member of the TMC family and due to the extremely high figure of merit (ZT), environmental compatibility and low toxicity, the Cu2Se has attracted much attention in recent developments of thermoelectrics [1]. This value, which is among highest for single crystalline compounds was notably enhanced from 1.5 at 100K to 1.7−1.8 at 700 ˚C by the introduction of nanoscale precipitates through fast quenching [1, 2]. Despite some reports on samples with quite high Cu deficiency [3], a comprehensive picture of Cu2Se transport properties at low temperatures is still not clear. Therefore, we present here investigation of thermoelectric transport properties of Cu2Se at low temperatures. The phase diagram of the Cu-Se system and more specifically Cu2-xSe phase has been intensively investigated previously, but nevertheless, data differ across literature [4, 5]. The properties of Cu2-xSe phase considerably depend on x and so does the transition temperature from low- to high-temperature phase. Our results and non- stoichiometric growth method used for growing crystals are consistent that sample investigated here is close to phase boundary and due to this more metallic. This fact enabled us to see more clearly specific transitions in low-temperature phase but on the other hand it is not completely clear if the sample is single crystal.

Cu2Se, transport properties

Poster je proglašen najboljim posterom ECMetAC Days 2018