High-order harmonics generation in MoS2 nanosheets in the presence of CdSe and CdSe/V2O5 quantum dots

Engineering nonlinear optical responses in two-dimensional materials via heterostructure design is emerging as a powerful approach for next-generation photonic devices. Although perturbative nonlinear effects in these systems are well studied, their connection to nonperturbative processes such as high-harmonic generation (HHG) remains largely unexplored. Here, we investigate the HHG from few-layer MoS2 nanosheets integrated with CdSe and passivated CdSe/V2O5 quantum dots (QDs). The hybrid structures exhibit pronounced enhancement in harmonic intensity and a clear extension of the harmonic cutoff relative to pristine MoS2. We demonstrate that interfacial charge-transfer dynamics—previously associated with the dominant contribution to the third-order susceptibility χ(3)—also govern the efficiency of HHG, thereby establishing a direct link between perturbative and nonperturbative regimes in these 0D–2D hybrids. The carrier injection from the QDs increases the electron–hole population participating in HHG, while the moderated response in passivated QD systems highlights the role of interfacial potential barriers. These results provide a unified physical picture of nonlinear optical processes in hybrid nanostructures and offer design principles for enhancing coherent light generation.