Department of Electrical Engineering and Graphene Research Center, Korea Advanced Institute of Science and Technology (KAIST) , Daejeon 305-701, Republic of Korea.
ACS Nano. 2014 Jul 22;8(7):6655-62. doi: 10.1021/nn405685j. Epub 2014 Jul 11.
Layered structures of transition metal dichalcogenides stacked by van der Waals interactions are now attracting the attention of many researchers because they have fascinating electronic, optical, thermoelectric, and catalytic properties emerging at the monolayer limit. However, the commonly used methods for preparing monolayers have limitations of low yield and poor extendibility into large-area applications. Herein, we demonstrate the synthesis of large-area MoSe2 with high quality and uniformity by selenization of MoO3 via chemical vapor deposition on arbitrary substrates such as SiO2 and sapphire. The resultant monolayer was intrinsically doped, as evidenced by the formation of charged excitons under low-temperature photoluminescence analysis. A van der Waals heterostructure of MoSe2 on graphene was also demonstrated. Interestingly, the MoSe2/graphene heterostructures show strong quenching of the characteristic photoluminescence from MoSe2, indicating the rapid transfer of photogenerated charge carriers between MoSe2 and graphene. The development of highly controlled heterostructures of two-dimensional materials will further promote advances in the physics and chemistry of reduced dimensional systems and will provide novel applications in electronics and optoelectronics.
层状过渡金属二卤化物通过范德华相互作用堆叠的结构现在引起了许多研究人员的关注，因为它们在单层极限处具有令人着迷的电子、光学、热电和催化性能。然而，常用的制备单层的方法存在产量低和难以扩展到大面积应用的局限性。在此，我们通过在任意衬底（如 SiO2 和蓝宝石）上通过化学气相沉积将 MoO3 硒化来展示大面积高质量和均匀性的 MoSe2 的合成。低温光致发光分析表明，所得到的单层是本征掺杂的，形成了带电激子。还展示了 MoSe2 在石墨烯上的范德华异质结构。有趣的是，MoSe2/石墨烯异质结构表现出 MoSe2 特征光致发光的强烈猝灭，表明光生电荷载流子在 MoSe2 和石墨烯之间的快速转移。二维材料的高度可控异质结构的发展将进一步推动降低维度系统的物理和化学的进展，并为电子学和光电子学提供新的应用。
