Engineering Exciton g ‐Factors With Light in Type‐II Heterostructures

ABSTRACT

Tunability of Landé g ‐factors associated with a single‐type of carrier in semiconductors remains a critical challenge, as precise control over spin physics is essential for advancing spintronic applications. At the same time, developing fast, field‐free tuning mechanisms is highly desirable. Here, we demonstrate that type‐II heterostructures provide an effective and scalable platform for robust optical manipulation of the g ‐factor using only the intensity of the incident light. By engineering wavefunction localization and overlap through the Coulomb attraction between spatially separated carriers, we have achieved a 1.5‐fold change in the excitonic g ‐factor solely by adjusting light intensity. Band structure simulations incorporating densities of photoexcited carriers confirm that this tuning mechanism arises from the delocalized carrier in the type‐II configuration. This approach enables a route for highly localized optical spin control, bridging a gap between spintronics and photonics. By eliminating the need for complex external fields, our findings open new avenues for g ‐factor engineering in well‐established semiconductor platforms.