Phase Engineering of Low‐Dimensional Quantum Materials for Photodetectors

ABSTRACT Low‐dimensional quantum materials, including transition metal dichalcogenides (TMDs), transition metal oxides (TMOs), and transition metal tellurides (TMTs), exhibit tunable phase transitions (2H, 3R, 1T) with distinct electronic and optical properties, rendering them ideal for advanced optoelectronic applications. TMDs possess layered structures with polymorphic phases, TMOs display metal‐insulator transitions, and TMTs exhibit charge density wave states and superconductivity, collectively enabling innovative device architectures. Phase engineering facilitates precise control over these phases via external stimuli, including temperature‐induced transitions in TMDs, electric field‐driven semiconductor‐to‐semimetal shifts, light‐induced homojunction formation, and strain‐mediated reduction of transition barriers. These methods modulate electronic structures, enhancing photodetector performance through gradient‐bandgap homo/heterojunctions for superior sensitivity, expanded spectral ranges, and multi‐state functionality. This review provides a comprehensive analysis of the structural attributes, phase engineering mechanisms, and their impacts on optimizing photodetectors, offering critical insights for advancing phase‐engineered low‐dimensional materials and high‐performance optoelectronic devices.