Strain Effects To Optimize Thermoelectric Properties of Doped Bi2O2Se via Tran–Blaha Modified Becke–Johnson Density Functional Theory

Electronic and transport properties of Bi2O2Se under strain are calculated using Tran–Blaha modified Becke–Johnson (TB-mBJGGA) potential and semiclassical Boltzmann transport theories. The electronic band gap decreases with tensile and compressive in-plane strain. We predict that the n-type Seebeck coefficient can be increased under compressive in-plane strain, while the p-type Seebeck coefficient can be increased under tensile in-plane strain. Further, the power factor of n-type doping Bi2O2Se can be increased under compressive in-plane strain, while that of p-type doping Bi2O2Se can be increased under tensile in-plane strain. For p-type doping Bi2O2Se, large thermoelectric figure of merit (ZT ≈ 1.42) could be obtained under tensile strain (2.3%) at 800 K. Moreover, a higher ZT ≈ 1.76 could be achieved along the ZZ direction. This study demonstrates that the electronic and thermoelectric properties can be controlled by strain engineering in thermoelectric material.