二维过渡金属硫族化合物能谷极化特性调控及其旋光发光二极管的研制

Monolayers of two-dimensional (2D) transition-metal dichalcogenides (TMDs) have exhibited great potential in electrical and optoelectronic device applications, and also become the promising candidates for spintronics and valleytronics, owing to the direct band gap in visible range, strong photoluminescence (PL), and stable excitons with large binding energy, as well as valley polarization. In this project, we will first explore the controllable growth technique of chemical vapor deposition for large-area 2D TMD monolayer and few-layer films with high quality and uniformly controllable thickness, as well as their heterostructures. Subsequently, the effects of the different stacking sequences and angles of the homostructures and heterostructures on their excitonic properties and valley polarization, together with the physical mechanisms will be studied. Furthermore, we will design and fabricate the vertical p-i-n heterojuction valley-light emitting diodes with CVD-grown 2D TMDs and their heterostructures as the active region. The chiral electroluminescence (EL) will be achieved under the forward injection current and the chirality contrast of the EL will be effectively tuned by changing the forward current. Additionally, the further study on the physical mechanisms of the influences of injection current on the chirality contrast of the EL will also be carried out. And the optimization about the structure design and fabrication processing of the devices will be excuted to enhance the electrical and optical performance of the valley-light emitting diodes. These works offer some references for the electrical modulation of valley polarization in 2D TMDs and open up new opportunities for the emerging valley-based optoelectronics.

二维过渡金属硫族化合物单层材料具有可见光范围内的直接带隙、强光致发光和稳定丰富的激子，以及能谷极化特性，在电子和光电子领域显示出了广泛的应用前景，并成为研究自旋电子学和能谷电子学的理想材料。本项目将采用化学气相沉积方法，生长大面积、高质量以及厚度均匀可控的二维过渡金属硫族化合物单层、少层薄膜材料及其异质结构，探索其关键性可控制备技术。在此基础上，研究不同堆垛模式对二维过渡金属硫族化合物同质和异质结构的激子发光偏振特性和能谷极化特性的影响，阐明相关的内在机理。进而设计和制备以二维过渡金属硫族化合物及其异质结构为有源区的p-i-n垂直异质结旋光发光二极管，通过改变注入电流大小实现对器件电致发光圆偏振性及圆极化率的有效调控，探究其调节规律及内在机制，建立能谷极化特性的电学调控手段，并进一步优化器件结构和制备工艺，提高器件发光性能。

二维过渡金属硫族化合物单层材料具有可见光范围内的直接带隙、强光致发光和稳定丰富的激子，以及能谷极化特性，在电子和光电子领域显示出了广泛的应用前景，并成为研究自旋电子学和能谷电子学的理想材料。因此，本项目采用化学气相沉积方法，结合对准转移法，探索大面积、高质量及厚度均匀的二维过渡金属硫族化合物薄膜材料的可控生长及其异质结构的制备。在此基础上，研究不同堆垛角度的二维过渡金属硫族化合物异质结构的光学特性及二维磁性材料/单层过渡金属硫族化合物堆垛异质结构的能谷极化特性，阐明相关的内在机理。进而设计和制备设计和制备以二维过渡金属硫族化合物为有源区的p-i-n垂直异质结旋光发光二极管，通过改变注入电流大小实现对器件电致发光圆偏振性及圆极化率的有效调控，探究其调节规律，建立能谷极化特性的电学调控手段。本项目的实施对基于过渡金属硫族化合物及其异质结构的旋光发光二极管的实现，具有重要的科学和应用价值。