Heteroatomic Engineering in Chemical Vapor Transport‐Grown 2D Single Crystals: Electronic Modulation and Emergent Quantum Phenomena

Layered transition‐metal dichalcogenides (TMDs) have emerged as an incipient class of low‐dimensional quantum materials owing to their highly tunable electronic, optical, magnetic, and catalytic properties. In recent years, controlled electronic modulation through substitution, intercalation, surface doping, and interstitial doping has become an effective strategy for tailoring the intrinsic physical properties, introducing extra degrees of freedom and inducing emergent quantum phenomena in TMD single crystals. This review summarizes recent progress in electronically modulated layered TMD single crystals synthesized primarily via chemical vapor transport (CVT) methods. Particularly emphasizing on different heteroatomic incorporation strategies and their influence on crystal structure, charge transfer, band structure evolution, magnetic ordering, topological properties, charge‐density waves, and phase transitions. Advanced characterization techniques including synchrotron‐based X‐ray spectroscopies, X‐ray photoelectron spectroscopy, scanning tunneling microscopy, scanning transmission electron microscopy, and angle‐resolved photoemission spectroscopy are discussed in detail for understanding the structural and electronic modifications induced by electronic modulation. Furthermore, the correlation between electronic structure engineering and resultant transport, magnetic, and optoelectronic properties is highlighted alongside recent advances in device‐oriented applications. Finally, the review discusses current challenges, post‐treatment strategies, and future perspectives for designing next‐generation electron‐modulated 2D quantum materials for electronic, spintronic, and quantum technologies.