Ripples in Two‐Dimensional Transition Metal Sulfides: Formation Mechanism, Optoelectronic Regulation, and Application Prospects

ABSTRACT As integrated circuit technology approaches its physical limits in the post‐Moore era, transition metal sulfides, with atomic‐scale thickness and exceptional electrical properties, have emerged as promising channel materials. The commonly occurring ripple strain, previously considered a fabrication defect to be overcome, has evolved into an actively controllable dimension with potential applications. This review first analyzes two types of formation mechanisms of ripple strain: one is a spontaneous process governed by thermodynamic fluctuations, substrate coupling, lattice mismatch, and mismatched thermal expansion coefficients; the other is based on artificial control strategies, such as substrate morphology engineering, strain transfer through flexible substrates, and field‐induced modifications, with a comparison of their controllability and limitations. The paper further examines how inhomogeneous strain fields profoundly alter the optoelectronic properties of materials through multiple physical channels. In particular, interface strain coupling in heterojunction systems offers a new paradigm for band engineering and quantum state manipulation. Although challenges remain in many aspects, the development of atomically precise strain fabrication processes and robust integration strategies holds promise for ripple strain engineering, playing a key role in tunable optoelectronic devices, high‐performance sensors, and on‐chip quantum information processing, advancing two‐dimensional materials from fundamental research to functional applications.