Thermoelectric properties of bilayer phosphorene under tensile strain

The thermoelectric power factor of bilayer phosphorene is investigated by performing first-principle calculations based on density functional theory combined with semiclassical Boltzmann transport theory. Our simulations show that the thermoelectric performance of phosphorene strongly depends on the interlayer coupling, the direction of the temperature gradient, and the direction of strain. We find that the interlayer coupling oppositely affects the power factor induced by the temperature gradient along either the zigzag direction or the armchair direction; the power factor under the effect of the temperature gradient is larger for monolayer (bilayer) phosphorene along the armchair (zigzag) direction. We also show that the power factor for bilayer phosphorene monotonically increases as a function of tensile strain up to 6%, despite the direction of strain. Above a strain of 6%, the power factor continues to increase with increasing strain along the armchair direction, while it decreases with increasing strain in the zigzag direction. Copyright (c) 2016 John Wiley & Sons, Ltd.