Photodetection properties of MXenes/GeC vertical heterojunctions

Using the first-principles calculations to investigate the photodetection properties of MXenes/GeC (germanium carbide) vertical heterojunctions. The results reveal a type-II band alignment, with Hf₂CO₂/GeC and GeC/Zr₂CO₂exhibiting indirect band gaps of 1.23 eV and 0.85 eV, respectively. Holes localize in GeC, while electrons are found in X₂CO₂, resulting in a net charge transfer of 0.02 e from GeC to X₂CO₂, which induces a built-in electric field. These heterostructures demonstrate strong broadband absorption spanning ultraviolet to visible regions. In the case of GeC/Zr₂CO_2,the photocurrent reaches its maximum value of 651.94a02/photonat 2.80 eV. For Hf₂CO₂/GeC, the extinction ratio peaks at 154.73 in the infrared and visible spectra. The maximum hole mobility of Hf₂CO₂/GeC heterojunction has been measured at 6.90 × 10³cm²Vs^-1along the zigzag direction. Notably, these two types of heterostructures exhibit potential for high-efficiency optoelectronic devices.