石墨烯对电致激发表面等离激元的调制特性研究

Surface plasmon polaritons (SPPs), which are electromagnetic modes confined along metal/dielectric interfaces, have attracted great interests in many application fields, especially plasmonic integrated circuits. The plasmonic circuitry is thought as a promising candidate for future information technology because it can be much faster than its electronic counterpart and break the diffraction-limited size of the photonic circuitry. Because of the momentum mismatch between photon and SPP, specific schemes for momentum matching are needed to couple the light from an independent light source to excite and modulate SPPs. The bulky light sources cannot scale down to nanoscale to be integrated into plasmonic circuits. In addition, the modulation for SPPs is only for one excited by light source, which hinders the integration of plasmonic devices. In this proposal, it is investigated that the electrical SPPs source is based on metal structure hybrid with high gain semiconductor QW material. According to the finite-domain time-difference simulation, the strong near-field coupling of metal/QW heterostructure is designed to get efficient excitation of SPPs. By electrical injection into QW, electron-hole pairs are generated in the QW and coupled into SPPs modes at the metal/semiconductor interface. The physical mechanism of the generation and propagation of SPPs is needed to be further analyzed. The optical characteristics of the electrical SPPs source is studied based on the experiments and theoretical analysis, so as to optimize its structure parameters. Graphene, a versatile, broadband optical material, has gate-voltage dependent optical conductivity. The combination of graphene and the electrical SPPs source is emerging as a suitable platform for electrically controlled plasmonic devices. It is needed to investigate of the interaction mechanism of carrier of semiconductor QW, surface plasmon and graphene. The modulation effect of graphene for the electrically excited SPPs is investigated. The electrically excited SPPs integrated with electrically modulation of SPPs is tried, which is the main innovation of this proposal. The electrically excited SPPs and its combination with graphene may bring new ideas for the realization of active plasmonic devices, which may play important roles for the development of plasmonic integrated circuits.

由于表面等离激元具有比电子快的速度、能突破光学衍射极限的优势，等离激元光子学成为微尺度光子学和纳尺度电子学联系的桥梁。表面等离激元的激发和调制是研究等离激元集成回路需要解决的首要问题。本项目拟通过半导体量子阱和金属的近场耦合作用实现表面等离激元的电致激发；在此基础上耦合石墨烯，利用石墨烯的动态调控特性实现对电致激发表面等离激元的调制作用；通过研究量子阱载流子与表面等离激元、表面等离激元与石墨烯的相互耦合作用，揭示调制过程及物理机制；探索表面等离激元电致激发和电学调制的集成方法。本项目的创新之处在于利用具有动态调控特性的石墨烯调制电致激发表面等离激元，进一步实现表面等离激元电致激发和电学调制的集成。本项目的研究将为有源等离激元器件光子学的实现提供新的思路和方法，对等离激元集成回路的发展起到重要的推动作用。

表面等离激元具有比电子快的速度、能突破光学衍射极限，等离激元光子学成为微光子学和纳电子学联系的桥梁，等离激元集成回路有望成为未来的信息技术。表面等离激元的激发和调制是研究等离激元集成回路需要解决的首要问题。本项目首次采用具有高增益特性、高量子效率的半导体量子阱和金属纳米结构基于近场耦合作用实现了表面等离激元电致激发源，在电注入的条件下，半导体GaAs量子阱中的电子-空穴对被激发后通过近场耦合作用直接激发表面等离激元，实现了表面等离激元的高效率电致激发。通过优化器件工艺和结构，获得了无直接光透射的表面等离激元电致激发源器件，提高了电致表面等离激元激发的纯粹性，这是对目前国际上已有表面等离激元电致激发源器件研究的一项重要改进。对于半导体/金属/介质/石墨烯耦合结构，获得了器件结构参数对石墨烯表面等离激元的调制规律。发现了结构衬底/石墨烯耦合结构对银纳米线上表面等离激元传导的调制作用规律。本项目的创新性研究将为有源等离激元器件的实现提供新的思路和方法，也将对等离激元集成回路的发展起到重要的推动作用。在本项目的资助下，发表与项目相关、已经标注本项目的SCI研究论文三篇，包括Adv. Funct. Mater.、Plasmonic、Appl. Surf. Sci.，发表会议论文四篇，申请发明专利7项，其中，关于表面等离激元电致激发源的专利和关于器件测试的专利均已获得授权。协助培养博士研究生一名。