基于带隙可调控特性的石墨烯/二硫化钼层状组装体的高效光探测器的研究

Unique bandgaps of two dimensional (2D) graphene (GH) and molybdenum disulfide (MoS2) exhibited distinctive layer-structure dependence. A layered assembly of GH/MoS2 could be prepared based on van der Waals forces and electron coupling at the interface to tune bandgaps, Fermi level and energy bands by electron interaction. In this project, the self-assembly of single-layer GH and MoS2 with specific electron structures and surface characteristics was controlled by the interaction between functional groups of GH and Mo precursors. 3D layered assemblies of GH/MoS2 were presented facilitated by the nucleation and growth of MoS2 at curved sp2-π bonds on GH sheets. This selective nucleation and growth on the template of GH controlled by interlayer effects were analyzed. The studies were focused on the tune of energy level, direct or indirect bandgaps and electron transition of GH/MoS2 assemblies by the control of layer-structure, interfacial effects and electron coupling between single-layer GH and MoS2. The sensitivity and reception to excitons with different wavelengths was enhanced by tuning the bandgap of GH/MoS2 assemblies, and switching times, ON/OFF ratios，reversibility and cycling stability of photocurrent because charge transfer and mobility were improved based on the studies of excitation, transition and relaxation. Advanced efficient photodetectors with high-resolution and prompt response were fabricated. Layered GH/MoS2 assemblies with a tunable bandgap settled a solid foundation for developing photodetectors for specific light sources.

二维片层结构的石墨烯（GH）和二硫化钼（MoS2）具有特异的带隙特性。二者层间的范德华力和电子耦合可控制GH与MoS2形成层状组装体，从而利用层间电子作用调控材料的带隙、费米能级和能带等结构。本项目在合成具有特定电子和表面结构的单层GH和MoS2的基础上，利用GH的官能团与Mo前驱体之间的相互作用，控制MoS2在含特定sp2-π键GH的曲面处成核生长，实现自组装和电子结构的调控，从而获得带隙可调的三维层状组装体。总结影响GH与MoS2层层组装的成核物理模板和相互作用。重点研究GH和MoS2的片层结构，界面特性和电子耦合作用对于改变其能级结构，直接或间接带隙和电子跃迁的影响规律。通过带隙结构的调控，显著提高对不同频带光源的接收和感应的能力，改善光电流的响应速率、开关比、可逆性和循环稳定性，揭示其在光激发跃迁、弛豫过程中的作用，为制作快速响应、高分辨光探测器，实现其对特定光源探测的可控奠定基础

二维片层结构的石墨烯（GH）和二硫化钼（MoS2）具有特异的带隙特性。二者之间的范德华力可控制GH与MoS2形成层状组装体，从而利用层间电子作用调控材料的带隙、费米能级和能带等结构。本项目通过低压化学气相沉积法生长了尺寸可达厘米级的单/双层的MoS2/GH异质结，利用GH的官能团与Mo前驱体之间的相互作用，控制MoS2在GH表面的均匀生长；利用硒掺杂实现了带隙在1.66~1.82eV范围内可调。重点研究GH和MoS2的片层结构，掺杂比例、界面特性对于改变其能级结构和电子跃迁的影响规律。以MoS2/GH层状异质结为基础构建了多个光电晶体管，提高了对不同波长光的响应能力，改善光电流的响应速率、开关比和循环稳定性。其光电流可达到12.7 μA，其响应时间为494 ms且响应度可以达到40.64 mA/W，提高了对不同波长光的响应能力，改善光电流的响应速率、开关比和循环稳定性，为后续深入设计并构建基于层状异质结的光电晶体管或探测器提供了材料基础。