量子点/石墨烯异质薄膜外延构筑及高灵敏光电转换特性研究

The ultrafast photoelectric response based on graphene breaks through the traditional photoelectric detection, and plays an important role for the development of new type of photoelectric detector.However, due to zero eV bandgap results its low quantum efficiency and limit its application. For the understanding of the precision building of quantum dot/graphene heterogeneous structure and enhanced response mechanism remains limited, and also lack the effective adjusted measures. This proposal is put forward using stark effect to control quantum excitation efficiency, and revealing the collaborative mechanism between the electric field, stimulate photon and tunneling current. Studying the relationship of the microstructure and photoelectric response between quantum dots/graphene heterogeneous film in detail. Further developing accurate constructing quantum dots/graphene interface technology based on electrochemical atomic layer epitaxy method, and exploring the interface electron tunneling method based on electric field enhancement and controllable modulating the quantum tunneling effect. The study will benefit for the application of graphene in optical detection and storage, photoelectric display technology and ultrahigh speed signal processing.

石墨烯超快光电响应特性的发现，突破了传统光电探测的认知范畴，为发展新型光电探测器件提供了重要的依据。但石墨烯本身的零帯隙特点导致其内量子产率较低，进而限制了其应用范围，针对量子增强型石墨烯光电器件的精准构筑手段缺乏和响应增强机制规律不明晰的基础问题。本项目提出利用斯塔克效应电控调制量子激发效率的方法，系统研究量子点/石墨烯异质薄膜的微观结构与光电响应的关系，揭示外加电场、隧穿电流与激发光子之间的协同作用机制；进一步发展基于电化学原子层外延法进行量子点/石墨烯界面精确构筑的技术；探索基于电场控制增强界面电子隧穿的方法，并对量子增强效应的可控调制进行实验验证。本项研究为石墨烯在光探测与存储、光电显示技术及超高速信号处理中的应用研究奠定基础。

本项目的研究内容主要集中在石墨烯/量子点异质外延结构的可控制备与光电探测器响应机制方面的研究。主要包括以下几个方面： 1、高质量石墨烯材料的可控制备技术。解决了大尺寸石墨烯单晶薄膜外延生长、石墨烯纳米墙的低温生长等关键技术，特别发展了基于微波等离子化学气相沉积法的石墨烯低温制备技术、实现了晶圆级石墨烯纳米墙薄膜的低温生长，实现了与传统MEMS加工工艺的兼容，为石墨烯材料在光热型探测应用方面奠定材料基础; 2、PbS量子点/石墨烯异质外延构筑技术。发展了电化学原子外延法在石墨烯表面制备PbS量子点的新方法，克服了胶体法与化学浴沉积法控制量子点尺寸与导电性等方面的难点，实现异质结构的良好外延制备。同时，通过引入极化结构，实现了PbS纳米棒的定向外延; 3、异质结构探测器微纳制作。采用微纳米加工工艺和技术实现了PbS/石墨烯异质结构光电探测器的制作，实现研制了石墨烯/PbS量子点的光电探测器，比探测率约为3.3 x109 Jones，响应时间约为1.8ms; 4、发展基于量子点/石墨烯薄膜的光电探测器集成技术。实现高灵敏光电探测器原型器件的研制，应用于室温光电探测。研制低成本、高集成度的光电探测器探测器，探测范围为1-3μm，利用量子点的高灵敏探测特性，实现中波非制冷红外探测具有重要意义。