State Key Laboratory of Silicon Materials, School of Materials Science and Engineering, Zhejiang University , Hangzhou, Zhejiang 310027, P. R. China.
CAS Key Laboratory of Standardization and Measurement for Nanotechnology, CAS Center for Excellence in Nanoscience, National Center for Nanoscience and Technology , Beijing 100190, P. R. China.
ACS Nano. 2017 Apr 25;11(4):4328-4336. doi: 10.1021/acsnano.7b01537. Epub 2017 Mar 27.
Stacked transition-metal dichalcogenides on hexagonal boron nitride (h-BN) are platforms for high-performance electronic devices. However, such vertical stacks are usually constructed by the layer-by-layer polymer-assisted transfer of mechanically exfoliated layers. This inevitably causes interfacial contamination and device performance degradation. Herein, we develop a two-step, low-pressure chemical vapor deposition synthetic strategy incorporating the direct growth of monolayer h-BN on Au foil with the subsequent growth of MoS. In such vertical stacks, the interactions between MoS and Au are diminished by the intervening h-BN layer, as evidenced by the appearance of photoluminescence in MoS. The weakened interfacial interactions facilitate the transfer of the MoS/h-BN stacks from Au to arbitrary substrates by an electrochemical bubbling method. Scanning tunneling microscope/spectroscopy characterization shows that the central h-BN layer partially blocks the metal-induced gap states in MoS/h-BN/Au foils. The work offers insight into the synthesis, transfer, and device performance optimization of such vertically stacked heterostructures.
在六方氮化硼 (h-BN) 上堆叠过渡金属二卤族化合物是高性能电子器件的平台。然而，这种垂直堆叠通常是通过逐层聚合物辅助转移机械剥离的层来构建的。这不可避免地会导致界面污染和器件性能下降。在此，我们开发了一种两步、低压化学气相沉积合成策略，包括在 Au 箔上直接生长单层 h-BN 以及随后生长 MoS。在这种垂直堆叠中，MoS 和 Au 之间的相互作用被中间的 h-BN 层减弱，这可以通过 MoS 中出现的光致发光来证明。减弱的界面相互作用通过电化学鼓泡法促进了 MoS/h-BN 堆叠从 Au 转移到任意衬底上。扫描隧道显微镜/光谱学表征表明，中间的 h-BN 层部分阻挡了 MoS/h-BN/Au 箔中金属诱导的能隙态。这项工作为这种垂直堆叠异质结构的合成、转移和器件性能优化提供了深入的了解。
