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 approximate to 1.42) could be obtained under tensile strain (2.3%) at 800 K. Moreover, a higher ZT approximate to 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.