混合维度工程在高效光电功能器件中的物理与应用研究

The new emerging low-dimensional semiconductors (including two-dimensional (2D) materials, colloidal quantum dots and perovskite nanocrystals) have shown the huge application potential in the field of modern physics, optoelectronics and energy. Meanwhile, they are also faced with some problems such as weak light absorption, low mobility and poor stability, respectively. Currently, numerous researches are focused on the property optimization of a single system, which has some certain limitations. On the basis of developing single components (such as the obtained 2D-TMDs, HgTe and Bi2Te3 quantum dots, CsPbX3 nanocrystals, X=Cl, Br, I), this project will adopt the innovative technology of mixed-dimensional engineering to assemble and mix the different dimensional materials, design and construct high-performance functional devices structures based on the new hybrid systems, develop and improve related physical mechanisms and device principles (such as photo-gating and photovoltaic effect). The goal is to optimize carrier transport, interface property and band alignment, thus to supplement the deficiency of each component and combine their advantages, finally achieve high performance and stable hybrids optoelectronics. Through the implementation of this project, we expect to promote the foundation and application development of new mixed-dimensional engineering technology in physical optoelectronics, and combing with the large-area 2D materials and large-volume quantum dots to lay a well research foundation for the practical application and long-term development of low-cost and high-efficiency optoelectronic devices.

新型低维半导体（二维、溶胶量子点和钙钛矿纳米晶）在当今物理光电能源领域显示出巨大应用潜力，然而也都分别面临着光吸收弱、迁移率低和稳定性差等问题。针对当前大量研究集中在单一体系性能优化上，具有一定的局限性。本项目将有效利用混合维度工程技术手段，在定向发展单组分材料基础上（如已掌握的CVD-TMDs；HgTe、Bi2Te3量子点；CsPbX3纳米晶，X=Cl,Br,I等），有目标导向的对不同维度材料进行组装和混合、设计构筑高效新型混合体系器件结构、发展完善相关物理机制和器件原理（如光栅、光伏等光电效应），来优化载流子输运、界面特性、带阶排列等，以弥补各单一组分不足并结合各自优势特性，实现制备高性能且稳定的光电功能器件。希望通过本项目的实施，推动新型混合维度工程技术在物理光电方面的基础和应用发展，并结合大面积二维和大体积量子点，为低成本高效功能器件相关实际应用和长远发展奠定良好的研究基础。

本项目围绕二维半导体材料、一维纳米线和零维量子点及其它们组成的混维体系，实现了高质量及大规模的新型混合维度材料体系的可控制备，构筑了偏振光探测器、光伏和晶体管等高性能光电器件，揭示了光伏和光栅效应等内在物理机制，提出了混合异质体系中的创新物理模型，指导促进其物理基础和应用发展。通过本项目实施，做出了系列创新成果，设计了新颖的器件结构，提高了器件性能，实现了新的功能，揭示了内在物理机制，推动了混合维度工程技术在新一代光电信息领域中的应用。本项目共发表SCI论文28篇（其中通讯作者论文26篇），申请国家发明专利10项，授权发明专利2项。项目负责人也获得了江西省自然科学一等奖。代表性工作如下：. （1）制备了2D-0D，即二维半导体和零维量子点的混维光电探测器，首次用梯度合金量子点CSZCS作为光敏层，光响应度提高了近300倍；（2）采用具有面内各向异性和线性二色性的窄带隙二维As0.4P0.6，获得了具有可重构操作模式的宽带和偏振灵敏探测器。在As0.4P0.6-MoTe2异质结中，光伏和光栅模式之间可以相互切换，且出现了二色性和偏振光电流的光学逆转现象；（3）设计了基于全二维（半金属MoTe2和半导体WS2）器件架构的高灵敏偏振光探测器，通过优化晶格取向，大幅度提高了偏振灵敏度，达到13；（4）设计了II型的GeAs/WS2异质结，在短红外波段（1310nm和1550nm），光电流各向异性比分别可达4.5和3.1；（5）用PVD方法生长了具有P型和面内各向异性结构的二维硒（Se）纳米薄片，并用N型WS2结合构建了用于偏振敏感和自驱动光电探测器的II型范德瓦尔斯异质结，成功作为多值逻辑触发器应用于微机控制系统。总之，本项目通过设计混合异质体系和新型器件结构，解决了一些关键问题，实现了高性能光电器件，推动了低维光电子领域的应用发展。