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**Abstract**
Controllable synthesis of high-quality graphene is essential for both fundamental research and practical applications, making it one of the most critical scientific challenges that require in-depth exploration. This field involves precise control over parameters such as size, shape, edge structure, crystal perfection, and doping, all of which are crucial for achieving optimal electrical performance.
Supported by the Chinese Academy of Sciences, the Ministry of Science and Technology, and the National Natural Science Foundation of China, researchers from the Institute of Organic Solids have made significant progress in controlling graphene synthesis. Their work has led to improved performance studies, with findings published in prestigious journals such as *Advanced Materials*, *NPG Asia Mater.*, *J. Am. Chem. Soc.*, and *Nat. Commun.*
One major breakthrough involves directly growing graphene on dielectric layers. Chemical vapor deposition (CVD) is widely used due to its ability to produce high-quality, large-area graphene. However, transferring the material to a dielectric substrate often leads to damage, wrinkles, and contamination. The ability to grow graphene directly on dielectrics offers great scientific value and technological potential, as it is compatible with current silicon-based electronics and simplifies device fabrication.
In earlier studies, researchers developed an oxygen-assisted method to grow graphene directly on silica substrates, later refining the process using a two-step CVD approach. This allowed for controlled nucleation and growth of high-quality graphene films on silicon nitride, with domain sizes reaching up to 1 mm. These films exhibit exceptional electrical properties, with electron mobility values of 1510 cm²/V·s in air and 1518 cm²/V·s in nitrogen—twice as high as those of graphene grown on silica. The study was published in *Advanced Materials* (2013, 25, 992) and featured on the cover.
Further work focused on the morphology and etching of single-crystal graphene. Researchers at the Chemical Solid State Laboratory previously created hexagonal single-crystal graphene on liquid copper using isotropic CVD. By manipulating gas ratios during the growth process, they achieved continuous control over the nucleation kinetics, leading to new metastable structures. The resulting graphene exhibited a unique six-fold symmetry, with boundary changes ranging from positive to negative curvature. This pattern closely resembles natural snowflakes, representing the first two-dimensional material to replicate such complex structures. The findings were published in *NPG Asia Mater.* (2013, 5, e36).
Building on this, the team explored graphene etching behavior. Traditional models suggest anisotropic etching based on crystalline symmetry. However, by adjusting the H₂/Ar gas ratio, they discovered that graphene can undergo fractal etching, moving beyond simple Euclidean patterns. This breakthrough was highlighted by *Chemistry World* with the headline “Carving graphene snowflakes with gases.†The results were published in *J. Am. Chem. Soc.* (2013, 135, 6431).
Additionally, researchers collaborated to create single-walled carbon nanotube/graphene junctions. These devices displayed strong rectification characteristics, with a switching ratio of ~160 and high photocurrent and photovoltage under intense light. The performance exceeded that of traditional pn junctions, suggesting potential for advanced photodetectors. The work was published in *Nat. Commun.* (2013, 4, 1374).
These studies reveal the complexity of non-equilibrium graphene growth and open new avenues for scalable, high-quality production. They also provide insights into broader material growth mechanisms and highlight the interplay between order and disorder, simplicity and complexity in nature.