Optical and Tuning Electronic Properties of GeC/MoS2 van der Waals heterostructures by electric field and strain: A First-Principles Study

Abstract Heterostructures have attracted significant attention because of their interlayer van der Waals interactions, in this work, six stacking models of GeC/MoS2 heterostructure were constructed, the AB stacking model has the lowest energy and the most stable interlayer spacing between GeC and MoS2 is 3.81 A. Based on First-principles calculations, we explored the structural, electronic and optical properties of GeC/MoS2 heterostructure and its response to electric field and biaxial strain. The results show that built-in electric field formed at the GeC/MoS2 interface, which effectively separated photo-generated electrons and holes. Meantime, the absorption of GeC/MoS2 located at ~200 nm was enhanced compared with monolayers. When the electric field strength increased from −0.7 V/A to 0.65 V/A, the band gap value of GeC/MoS2 heterostructure increased from 0eV to 1.21eV linearly, then decreased continuously to 0eV with the electric field strength increasing from 0.65 V/A to 0.8 V/A. Lastly, with the biaxial strain increasing from −6% to 5%, the gap value of GeC/MoS2 heterostructure increased slowly from 0 eV to 1.19eV, then decreased rapidly to 0 eV when the biaxial strain increased from 5% to 8%, the transitions of direct-to-indirect band gap and N-to-P type characteristic occurred when biaxial strain was 3% and −2% respectively. Results show that the GeC/MoS2 heterostructure has application prospects in ultraviolet, nanoelectronic, and pressure sensitive devices.