Reale Francesco, Palczynski Pawel, Amit Iddo, Jones Gareth F, Mehew Jake D, Bacon Agnes, Ni Na, Sherrell Peter C, Agnoli Stefano, Craciun Monica F, Russo Saverio, Mattevi Cecilia
Department of Materials, Imperial College, London, SW7 2AZ, UK.
Centre for Graphene Science, Department of Physics, University of Exeter, Stocker Road, Exeter, EX4 4QL, UK.
Sci Rep. 2017 Nov 2;7(1):14911. doi: 10.1038/s41598-017-14928-2.
The rise of atomically thin materials has the potential to enable a paradigm shift in modern technologies by introducing multi-functional materials in the semiconductor industry. To date the growth of high quality atomically thin semiconductors (e.g. WS) is one of the most pressing challenges to unleash the potential of these materials and the growth of mono- or bi-layers with high crystal quality is yet to see its full realization. Here, we show that the novel use of molecular precursors in the controlled synthesis of mono- and bi-layer WS leads to superior material quality compared to the widely used direct sulfidization of WO-based precursors. Record high room temperature charge carrier mobility up to 52 cm/Vs and ultra-sharp photoluminescence linewidth of just 36 meV over submillimeter areas demonstrate that the quality of this material supersedes also that of naturally occurring materials. By exploiting surface diffusion kinetics of W and S species adsorbed onto a substrate, a deterministic layer thickness control has also been achieved promoting the design of scalable synthesis routes.
原子级超薄材料的兴起，有可能通过在半导体行业引入多功能材料，实现现代技术的范式转变。迄今为止，高质量原子级超薄半导体（如WS）的生长是释放这些材料潜力最紧迫的挑战之一，高质量单或双层的生长尚未完全实现。在此，我们表明，与广泛使用的基于WO前驱体的直接硫化相比，在单双层WS的可控合成中新颖地使用分子前驱体可带来更高的材料质量。在高达52 cm²/V·s的室温电荷载流子迁移率以及亚毫米区域仅36 meV的超窄光致发光线宽，证明了这种材料的质量也超过了天然材料。通过利用吸附在衬底上的W和S物种的表面扩散动力学，还实现了确定性的层厚控制，推动了可扩展合成路线的设计。
