液态金属辅助CVD法制备二维Ga2Se3及其光探性能的研究

High responsivity and broadband photoresponse have always been the major challenges in the field of photodetectors. Ga2Se3 semiconductor is a suitable carrier for constructing high performance photodetectors due to its direct-bandgap properties, excellent photoconductivity and defect-induced broadband absorption. Due to reduced dimension and the interface materials properties, two-dimensional (2D) materials are extremely sensitive to structural defects, and the two-dimensionality of Ga2Se3 is expected to produce novel photoelectric properties. Therefore, realizing the controlled synthesis of 2D Ga2Se3 contributes to construction of high-performance photodetector. For the synthesis problems caused by the non-layered crystalline structure of Ga2Se3, in the project, we intend to adopt chemical vapor deposition (CVD) method and employ liquid metal gallium (Ga) as the precursor and substrate of the reaction, and use selenium (Se) powder as Se source, then control the evaporation of precursors though controlling temperature separately, thus controlling reaction rate and adjusting action mechanism, to achieve controlled synthesis of 2D Ga2Se3. On this basis, we evaluate its photoelectric properties and photodetection properties, and explore its luminescence mechanism, photocurrent generation mechanism and the factors affecting device performance, then optimize the device performance. This project will provide a new idea for synthesis of 2D Ga-based compounds, and it is expected to achieve the construction of 2D photodetectors with high responsivity and broadband photoresponse.

高响应度、宽光谱响应一直是光探测器领域的重大挑战。Ga2Se3半导体因具有直接带隙的属性、优异的光电导性能及缺陷诱导的宽光谱吸收等，是构筑高性能光探测器的合适载体。由于降低的维度和界面材料的属性，二维材料对结构缺陷异常敏感，Ga2Se3材料的二维化有望产生新颖的光电性能。因此，实现二维Ga2Se3的可控制备有助于构筑高性能的光探测器。针对Ga2Se3非层状晶体结构带来的制备难题，本项目拟采用化学气相沉积（CVD）法，以液态金属镓（Ga）作为反应的前驱体和衬底，以硒（Se）粉作为Se源，通过单独控温的方式控制前驱体的蒸发，从而控制反应速率、调整反应机制，实现二维Ga2Se3的可控制备。在此基础上，评估其光电性能和光探测性能，探究其发光机制、光电流产生机制及器件性能的影响因素，并优化器件的性能。本项目的开展将为二维Ga基化合物的制备提供新思路，有望实现高响应度、宽光谱响应的二维光探测器的构筑。

高响应度、宽光谱响应一直是光探测器领域的重大挑战。Ga2Se3半导体因具有直接带隙的属性、优异的光电导性能及缺陷诱导的宽光谱吸收等，是构筑高性能光探测器的合适载体。由于降低的维度和界面材料的属性，二维材料对结构缺陷异常敏感，Ga2Se3材料的二维化有望产生新颖的光电性能。因此，实现二维Ga2Se3的可控制备有助于构筑高性能的光探测器。针对Ga2Se3非层状晶体结构带来的制备难题，本项目采用空间限域的物理气相沉积法实现了高质量二维Ga2Se3的可控制备，在此基础上，评估其光电性能和光探测性能，探究其发光机制、光电流产生机制及器件性能的影响因素，基本实现了高响应度、宽光谱相应的光电探测器的构筑。项目执行期间，累计在Advanced science等期刊上发表SCI论文4篇，申请专利2项，获批陕西省科技厅重点研发计划项目一项，指导（共同指导）硕士生3名，其中已毕业的1名。通过本项目的实施，为申请人继续在二维材料与光电器件领域的研究奠定了坚实的基础。