Chemical vapour deposition (CVD) growth is capable of producing multiple single-crystal islands of atomically thin transition metal dichalcogenides (TMDs) over large areas. Subsequent merging of perfectly epitaxial domains can lead to single-crystal monolayer sheets, a step towards scalable production of high quality TMDs. For CVD growth to be effectively harnessed for such production it is necessary to be able to rapidly assess the quality of material across entire large area substrates. To date, characterisation has been limited to sub-0.1-mm² areas, where the properties measured are not necessarily representative of an entire sample. Here, we apply photoluminescence (PL) imaging and computer vision techniques to create an automated analysis for large area samples of monolayer TMDs, measuring the properties of island size, density of islands, relative PL intensity and homogeneity, and orientation of triangular domains. The analysis is applied to ×20 magnification optical microscopy images that completely map samples of WSe₂ on hBN, 5.0 mm × 5.0 mm in size, and MoSe₂–WS₂ on SiO₂/Si, 11.2 mm × 5.8 mm in size. Two prevailing orientations of epitaxial growth were observed in WSe₂ grown on hBN and four predominant orientations were observed in MoSe₂, initially grown on c-plane sapphire. The proposed analysis will greatly reduce the time needed to study freshly synthesised material over large area substrates and provide feedback to optimise growth conditions, advancing techniques to produce high quality TMD monolayer sheets for commercial applications.

化学气相沉积（CVD）的生长能够在大面积上产生原子薄的过渡金属二卤化金属（TMD）的多个单晶岛。完美外延域的后续合并可导致单晶单层片材，这是向可扩展生产高质量TMD迈出的一步。为了有效地利用CVD生长进行此类生产，必须能够快速评估整个大面积基板上材料的质量。迄今为止，表征仅限于小于0.1 mm ²所测量的特性不一定代表整个样品的区域。在这里，我们应用光致发光（PL）成像和计算机视觉技术来创建针对大面积单层TMD样品的自动化分析，测量岛大小，岛密度，相对PL强度和同质性以及三角形区域的方向的特性。该分析适用于×20放大倍率的光学显微镜图像，该图像将WSe _2的样品完全映射在尺寸为5.0 mm×5.0 mm的hBN上，而MoSe ₂ –WS _2的样品则映射在尺寸为11.2 mm×5.8 mm的SiO ₂ / Si上。在hBN上生长的WSe ₂中观察到两个主要的外延生长方向，在MoSe中观察到四个主要的取向。₂，最初生长在c面蓝宝石上。拟议的分析将大大减少在大面积基板上研究新鲜合成材料所需的时间，并提供反馈以优化生长条件，从而推进生产可用于商业用途的高质量TMD单层片材的技术。