Two-dimensional moiré heterostructures formed by stacking atomically thin crystals with a small twist angle have emerged as a powerful platform for engineering electronic and optical properties beyond those of the individual layers. In these systems, the long-range periodic potential generated by the moiré superlattice gives rise to novel excitonic, valley and polarization phenomena that are highly sensitive to lattice symmetry and interlayer coupling. This sensitivity offers exceptional opportunities for optoelectronic functionality, but it also exposes a critical limitation of current approaches. Once fabricated, the optical response of these systems is essentially fixed, which severely restricts their adaptability, scalability and integration into functional devices. Moreover, uncontrolled strain introduced during fabrication often acts as a parasitic effect, leading to inhomogeneity, poor reproducibility and ambiguous interpretation of experimental results. Addressing these challenges requires a paradigm shift in which strain is no longer treated as an unavoidable artifact, but as an active and controllable degree of freedom.
The PHOTOMOIRE project is motivated by the need to establish strain as a deterministic and reversible knob for controlling polarization and light–matter interactions in marginally twisted moiré heterostructures. By combining controlled nanofabrication, in-situ nanoscale characterization and device-oriented design, the project pursues three complementary objectives. First, it will develop robust fabrication routes for high-quality twisted moiré heterostructures. Second, it will implement a state-of-the-art experimental platform capable of probing optical and electronic properties at the nanoscale while applying strain in situ. Third, it will translate these advances into prototype polarization-sensitive optoelectronic devices based on moiré superlattices.
