Plasma-enhanced synthesis has emerged as a powerful approach for growing two-dimensional materials with precise control over their structural and electronic properties. Unlike conventional thermal methods, plasma-assisted growth offers unique advantages, including lower processing temperatures, enhanced reaction kinetics, and the ability to introduce controlled doping. This technique has been successfully applied to synthesize transition metal dichalcogenides like MoS2, hexagonal boron nitride (h-BN), and emerging MXenes, enabling tailored properties for electronic, optoelectronic, and catalytic applications.

The plasma environment consists of highly reactive species, including ions, electrons, and radicals, which interact with precursor materials to facilitate growth. By adjusting plasma parameters such as power, pressure, gas composition, and substrate bias, it is possible to influence nucleation density, layer thickness, and crystallinity. For instance, in the growth of MoS2, sulfur vacancies can be minimized by optimizing the H2S plasma flow rate, while nitrogen plasma treatment has been shown to introduce n-type doping in WS2 monolayers. The ability to tune these parameters makes plasma-assisted growth highly versatile for creating heterostructures and alloys with atomically sharp interfaces.

One of the key advantages of plasma-enhanced synthesis is the ability to grow high-quality 2D materials at relatively low temperatures. Conventional chemical vapor deposition of MoS2 typically requires temperatures above 800°C, whereas plasma-assisted processes can achieve monolayer growth at 500–600°C. This is particularly beneficial for integrating 2D materials with temperature-sensitive substrates or back-end-of-line semiconductor processing. The lower thermal budget also reduces unwanted reactions between the substrate and growing material, leading to cleaner interfaces.

The electronic properties of plasma-grown 2D materials can be finely tuned through controlled doping. For example, argon plasma treatment has been used to create sulfur vacancies in MoS2, which can then be passivated with nitrogen or oxygen to modify its electronic structure. In the case of h-BN, boron-rich or nitrogen-rich plasmas can be used to grow films with tailored band gaps and defect densities. Plasma exposure also allows for in-situ doping during growth, as demonstrated by the incorporation of carbon or fluorine into MXenes to alter their work function and conductivity.

Heterostructure formation is another area where plasma-assisted growth excels. Sequential growth of different 2D materials in the same plasma chamber enables the creation of sharp interfaces without contamination. For instance, vertical heterostructures of MoS2 and WS2 have been synthesized by switching precursor gases while maintaining the plasma environment. The absence of air exposure between layers minimizes interfacial defects, which is critical for achieving high carrier mobility in devices. Plasma-enhanced atomic layer deposition has also been used to grow alternating layers of h-BN and graphene with sub-nanometer precision.

The optical properties of plasma-grown 2D materials are strongly influenced by the growth conditions. Monolayer MoS2 synthesized in a sulfur-rich plasma exhibits strong photoluminescence with a narrow peak width, indicating low defect density. In contrast, films grown under sulfur-deficient conditions show quenched luminescence due to the formation of defects. Similarly, the band gap of h-BN can be tuned by varying the boron-to-nitrogen ratio in the plasma, with stoichiometric films exhibiting the largest band gap of around 6 eV. MXenes grown in fluorine-containing plasmas display unique plasmonic resonances that can be adjusted by controlling the fluorine termination.

Plasma conditions also play a critical role in determining the crystallinity and orientation of 2D materials. High-density plasmas with sufficient ion energy can promote lateral growth of large-domain films, while excessive ion bombardment can lead to amorphization. For example, MoS2 grown in a low-power plasma tends to form small, randomly oriented domains, whereas optimized plasma conditions yield centimeter-scale single-crystal films. The use of remote plasma configurations, where the substrate is placed outside the direct plasma region, has been shown to reduce damage while still benefiting from enhanced precursor dissociation.

Scalability is a significant advantage of plasma-assisted growth. Roll-to-roll plasma systems have been demonstrated for continuous synthesis of graphene and h-BN on flexible substrates. The fast growth rates achievable with plasma enhancement, often an order of magnitude higher than thermal CVD, make this approach attractive for industrial applications. Uniformity across large areas is facilitated by the ability to precisely control plasma parameters across the substrate, with thickness variations of less than 5% reported for 4-inch wafers.

Challenges remain in fully understanding the complex plasma-surface interactions during 2D material growth. The interplay between plasma species and surface reactions requires careful optimization to avoid excessive defect formation while maintaining high growth rates. Advanced diagnostics such as optical emission spectroscopy and mass spectrometry are being employed to monitor plasma composition in real time, enabling better control over the growth process. Future developments in plasma source design and process automation are expected to further improve the reproducibility and quality of plasma-grown 2D materials.

The unique capabilities of plasma-enhanced synthesis position it as a critical tool for advancing 2D material research and applications. From tunable electronic properties to scalable production, this method offers a pathway to integrate these materials into next-generation devices. As understanding of plasma-material interactions deepens, the range of accessible 2D materials and heterostructures will continue to expand, opening new possibilities in nanoelectronics, photonics, and energy technologies.