First principles study on the electronic and optical behavior of atomically thin MXene/MC (M = Si, Ge) heterostructures

Following the discovery of graphene, research on two-dimensional (2D) materials has surged. To enhance the performance and broaden the applications of these materials, heterostructures are formed by stacking two different layered materials through van der Waals (vdW) interactions. This study, based on first-principles calculations, explores the intriguing properties of heterostructures made from Zr 2 CO 2 , SiC, and GeC monolayers. The results indicate that the Zr 2 CO 2 /SiC and Zr 2 CO 2 /GeC vdW heterostructures retain their original band structure and exhibit robust thermal stability at 300 K. Additionally, the Zr 2 CO 2 /MC heterostructure, with an I-type band alignment, shows promise as a light-emitting device material. Charge transfer between Zr 2 CO 2 and SiC (or GeC) monolayers are obtained as 0.1459 | e | and 0.0425 | e |, respectively. The potential drop across the interface for Zr 2 CO 2 /SiC and Zr 2 CO 2 /GeC is 6.457 eV and 3.712 eV, respectively. Besides, the Zr 2 CO 2 /SiC vdW heterostructure presents excellent carrier mobility along the transport direction (about 3656 cm 2 V −1 ·s –1 ). These heterostructures exhibit remarkable optical absorption, further demonstrating the potential of Zr 2 CO 2 /MC for optoelectronic applications. This study provides valuable theoretical insights for designing photocatalytic and photovoltaic devices using heterostructures.