High thermoelectric figure of merit for GeS/phosphorene 2D heterostructures: A first-principles study

Abstract

2D materials, such as graphene, transition metal dichalcogenides, and black phosphorus (i.e., phosphorene), have attracted wide interest as efficient thermoelectric materials. Herein, we propose GeS/phosphorene (GeS/BP) heterostructure as a promising high-performance thermoelectric material. We have investigated the electronic structure and the thermoelectrical properties of the GeS/BP 2D system using first-principles calculations combined with the semi-classical Boltzmann transport theory. We have also addressed the effect of temperature and chemical potential on its transport properties. Our calculations revealed a high thermoelectrical figure of merit (ZT) of 2.53 for the GeS/BP system. Interestingly, ultrahigh room temperature ZT values amounting to 14.01 and 33.39 could be attained through p-type doping of the GeS/BP heterostructures. We ascribe the remarkably high ZT to the increase of the Seebeck coefficient in the system and the enhanced charge density redistribution at the GeS/BP interface. These findings highlight a promising strategy to achieve high-performance thermoelectric materials through nanostructuring of 2D materials.