Investigation of the electronic and thermoelectric properties of hydrogenated monolayer germanene under biaxial tensile and compressive strains by DFT approach

Abstract

Abstract Two-dimensional materials possess a great potential in thermoelectric devices. In this work, by using a combination of first-principles calculations and semiclassical Boltzmann transport theory, a systematic investigation of electronic and thermoelectric properties of hydrogenated monolayer germanene under biaxial strain is presented. The results show that in all cases, the thermoelectric performance of the n-type doping on the germanene is substantially superior than that of the p-type doping. In the p-type doping, increasing the tensile strain would result in increasing the power factor, and the strain +3% creates the highest power factor. However, in the n-type doping, increasing the compressive strain increases the power factor, and the strain −6% leads to the highest power factor. Under the strain of −6%, the peak of the power factor for n-type doping equals to 32.3⨯1010 W/K2ms; while this amount equals to 12.2⨯1010 W/K2ms for the pristine case, which in fact has increased as 2.8 times. The mentioned peak will reach 57.21⨯1010 W/K2ms at the temperature 800 K, which is very significant. These results show the enormous potential of hydrogenated monolayer germanene in the thermoelectric industry.