Improved thermoelectric transport properties of Ge4Se3Te through dimensionality reduction

Layered semiconducting Ge4Se3Te shows unusual bonding that suggests the possibility of unusual transport that may be favorable for thermoelectrics. We investigated the electronic transport properties in relation to thermoelectricity of Ge4Se3Te using Boltzmann transport theory based on first principles calculations. We find favorable properties of transport for the bulk. Additionally, we find that both the carrier mobility and power factor may be increased through dimensional reduction. The nature of the bonding, specifically the weak anharmonic bonds, can lead to phonon scattering and low lattice thermal conductivity. This combination leads to the potential for high thermoelectric performance for the monolayer, for both p-type and n-type if the carrier concentration is optimized. Based on the results, the values as high as ZT = 2.6 at 900 K may be achievable.