Zhou Jiadong, Kong Xianghua, Sekhar M Chandra, Lin Junhao, Le Goualher Frederic, Xu Rui, Wang Xiaowei, Chen Yu, Zhou Yao, Zhu Chao, Lu Wei, Liu Fucai, Tang Bijun, Guo Zenglong, Zhu Chao, Cheng Zhihai, Yu Ting, Suenaga Kazu, Sun Dong, Ji Wei, Liu Zheng
School of Materials Science and Engineering , Nanyang Technological University , 639798 Singapore.
Department of Physics and Centre for the Physics of Materials , McGill University , Montreal , Quebec H3A 2T8 , Canada.
ACS Nano. 2019 Oct 22;13(10):10929-10938. doi: 10.1021/acsnano.8b09479. Epub 2019 Sep 27.
PtSe, a layered two-dimensional transition-metal dichalcogenide (TMD), has drawn intensive attention owing to its layer-dependent band structure, high air stability, and spin-layer locking effect which can be used in various applications for next-generation optoelectronic and electronic devices or catalysis applications. However, synthesis of PtSe is highly challenging due to the low chemical reactivity of Pt sources. Here, we report the chemical vapor deposition of monolayer PtSe single crystals on MoSe. The periodic Moiré patterns from the vertically stacked heterostructure (PtSe/MoSe) are clearly identified annular dark-field scanning transmission electron microscopy. First-principles calculations show a type II band alignment and reveal interface states originating from the strong-weak interlayer coupling (SWIC) between PtSe and MoSe monolayers, which is supported by the electrostatic force microscopy imaging. Ultrafast hole transfer between PtSe and MoSe monolayers is observed in the PtSe/MoSe heterostructure, matching well with the theoretical results. Our study will shed light on the synthesis of Pt-based TMD heterostructures and boost the realization of SWIC-based optoelectronic devices.
PtSe是一种层状二维过渡金属二硫属化物（TMD），因其与层相关的能带结构、高空气稳定性以及自旋层锁定效应而备受关注，可用于下一代光电器件和电子器件的各种应用或催化应用。然而，由于铂源的化学反应性低，PtSe的合成极具挑战性。在此，我们报道了在MoSe上化学气相沉积单层PtSe单晶。通过环形暗场扫描透射电子显微镜可以清晰地识别出垂直堆叠的异质结构（PtSe/MoSe）产生的周期性莫尔条纹。第一性原理计算表明存在II型能带排列，并揭示了源自PtSe和MoSe单层之间强弱层间耦合（SWIC）的界面态，这得到了静电力显微镜成像的支持。在PtSe/MoSe异质结构中观察到了PtSe和MoSe单层之间的超快空穴转移，与理论结果吻合良好。我们的研究将为基于铂的TMD异质结构的合成提供启示，并推动基于SWIC的光电器件的实现。
