Precise Construction and Growth of Submillimeter Two-Dimensional WSe₂ and MoSe₂ Monolayers

Currently, as shown by large-scale research on two-dimensional materials in the field of nanoelectronics and catalysis, the construction of large-area two-dimensional materials is crucial for the development of devices and their application in photovoltaics, sensing, optoelectronics, and energy generation/storage. Here, using atmospheric-pressure chemical vapor deposition, we developed a method to regulate growth conditions according to the growth mechanism for WSe2 and MoSe2 materials. By accurately controlling the hydrogen flux within the range of 1 sccm and the distance between the precursor and the substrate, we obtained large-size films of single atomic layers with thicknesses of only about 1 nm. When growing the samples, we could not only obtain a 100 percent proportion of samples with the same shape, but the samples could also be glued into pieces of 700 & mu;m and above in size, changing the shape and making it possible to reach the millimeter/submillimeter level visible to the naked eye. Our method is an effective method for the growth of large-area films with universal applicability.