Lateral transition-metal dichalcogenide and their heterostructures have attracted substantial attention, but there lacks a simple approach to produce large-scaled optoelectronic devices with graded composition. In particular, the incorporation of substitution and doping into heterostructure formation is rarely reported. Here, we demonstrate growth of a composition graded doped lateral WSe₂/WS₂ heterostructure by ambient pressure chemical vapor deposition in a single heat cycle. Through Raman and photoluminescence spectroscopy, we demonstrate that the monolayer heterostructure exhibits a clear interface between two domains and a graded composition distribution in each domain. The coexistence of two distinct doping modes, i.e., interstitial and substitutional doping, was verified experimentally. A distinct three-stage growth mechanism consisting of nucleation, epitaxial growth, and substitution was proposed. Electrical transport measurements reveal that this lateral heterostructure has representative characteristics of a photodiodes. The optoelectronic device based on the lateral WSe₂/WS₂ heterostructure shows improved photodetection performance in terms of a reasonable responsivity and a large photoactive area

中文翻译：

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超薄成分梯度掺杂的横向WSe ₂ / WS ₂异质结构的合成

横向过渡金属二硫化氢及其异质结构引起了人们的广泛关注，但是缺乏一种简单的方法来生产具有梯度成分的大规模光电器件。特别地，很少报道将取代和掺杂结合到异质结构形成中。在这里，我们演示了成分渐变掺杂的横向WSe ₂ / WS _2的生长在单个热循环中通过环境压力化学气相沉积产生的异质结构。通过拉曼光谱和光致发光光谱，我们证明了单层异质结构在两个域之间表现出清晰的界面，并且每个域中的组分分布呈梯度分布。实验验证了两种不同的掺杂模式的共存，即间隙掺杂和替代掺杂。提出了由成核，外延生长和取代组成的独特的三阶段生长机理。电传输测量表明该横向异质结构具有光电二极管的代表性特征。基于横向WSe ₂ / WS ₂的光电器件 异质结构在合理的响应度和较大的光敏面积方面显示出改进的光电检测性能