dichalcogenidescontrol

Dichalcogenides control refers to the deliberate manipulation of the structural, electronic, and optical properties of transition metal dichalcogenides (TMDs), a class of layered compounds with the general formula MX2 where M is a transition metal such as molybdenum or tungsten and X is a chalcogen such as sulfur or selenium. In its monolayer form, many TMDs such as MoS2 and WS2 exhibit a direct bandgap and strong photoluminescence, while thicker layers show indirect gaps. Controlling these materials involves adjusting thickness, composition, strain, defects, and the surrounding environment to achieve desired performance for electronics, optoelectronics, and catalysis.

Key control strategies include layer-number control through exfoliation or growth, chemical substitution and doping, strain engineering by substrate choices or bending, and defect engineering through controlled vacancies or intercalants. Doping and intercalation tune carrier concentration and Fermi level. Heterostructuring with other 2D materials such as graphene or hexagonal boron nitride creates type-II band alignments and new excitonic pathways. Growth parameter control in chemical vapor deposition or molecular beam epitaxy determines grain size, orientation, and layer uniformity. Encapsulation in inert dielectrics improves stability and sharpens optical signals by reducing environmental screening and degradation.

Applications span field-effect transistors, photodetectors, light emission, and photocatalysis, with notable activity in hydrogen evolution reaction on certain TMD edges. Challenges include scalable uniform synthesis, contact resistance, defect management, and reproducibility across batches. Ongoing research focuses on understanding exciton dynamics, valley physics, and charge transfer in heterostructures to enable reliable devices.