Thermoelectric properties of GeSe

A peak figure of merit, zT of ∼0.2 at 700 K is achieved in Ag0.01Ge0.79Sn0.2Se, a composition with the highest carrier concentration, through a combination method of doping and alloying. The transport properties can be well described by a single parabolic band model which further enables a prediction on the maximal zT of ∼0.6 at 700 K and the corresponding carrier concentration of ∼5 × 1019 cm−3, indicating that GeSe shows a potentially high thermoelectric figure of merit but requires a much higher carrier concentration.