A Type-II GaS/GeC van der waals heterostructure with adjustable electronic properties under external electric field and biaxial strain

van der Waals Heterostructure (vdwH) is favoured by researchers due to its distinctive structure and excellent properties. Thanks to the first principles, the geometric stability, and electronic and optical properties of GaS/ GeC vdwH are researched in detail. The results demonstrate GaS/GeC vdwH has a classic Type-II band arrangement with an indirect band gap of 0.834 eV and good stability. The different configurations, changing the layer spacing, and applying external electric field as well as the strain will influence the electronic and optical properties of GaS/GeC vdwH. Particularly worth mentioning is that when the applied electric field strength of the original configuration reaches-0.8 V/& ANGS; and 0.9 V/& ANGS; or the biaxial strain arrives at 6%, GaS/GeC vdwH will transform from semiconductor to metal. The transformed two configurations change from indirect band gap to direct under positive electric field and compressive strain, respectively. Besides, GaS/GeC vdwH shows better optical absorption performance than monolayer in the ultraviolet region. Strain and electric field can make the absorption peak of GaS/GeC vdwH redshift, and the same as other configurations can enhance the optical absorption capacity of GaS/GeC vdwH in the near ultraviolet and visible regions to different degrees. These results indicate that GaS/GeC vdwH is a good candidate for nanoscale and optoelectronic devices in the future.