Synthesis of complex two-dimensional heterostructures with tailored optoelectronic properties

具有定制光电特性的复杂二维异质结构的合成

• 批准号: 510528670
• 负责人: Privatdozent Dr. Tobias Kipp
• 金额: --
• 依托单位: Institut für Physikalische Chemie
• 依托单位国家: 德国
• 项目类别: Research Grants
• 资助国家: 德国
• 项目状态: 未结题
• 来源: https://gepris.dfg.de/gepris/projekt/510528670?language=en
• 关键词: Synthesis; complex; two; dimensional; heterostructures

Complex semiconductor/semiconductor heteronanostructures or metal/semiconductor hybrid structures are of great interest for various applications in optoelectronics. Semiconductor heterostructures can be used in photovoltaics by separating photo-generated electron-hole pairs across the hetero-interface. Conversely, charge carriers injected into the heterostructure can recombine in the interface region, emitting light. Metal/semiconductor hybrid structures are ideally suited for photocatalysis, e.g., by transferring electrons optically generated in the semiconductor material to attached metal particles, which can reduce protons to hydrogen. In this project, chemical synthesis methods for various two-dimensional hetero- and hybrid nanostructures will be developed. By controlled epitaxial growth of one semiconductor material onto another, SnSe/SnS core/shell nanosheets are to be synthesized, for example, in which the valence band edge progression can be selectively adjusted via anion variation. Furthermore, cation exchange reactions will be used to synthesize Janus-like CuS/CdS hetero-nanosheets starting from CuS nanosheets, in which the conduction band energy and thus the electron localization is controlled via the cation gradient. Finally, the targeted growth of metal nanocrystals on the edges of the nanosheets should lead to hybrid structures in which the photo-generated electrons are localized in the edge metal particles, resulting in particularly efficient photocatalysts. In addition to the chemical synthesis of the nanosheets, the research of their optoelectronic properties is in the foreground of this project. An important goal here is to directly follow the localization of the photogenerated charge carriers in individual hybrid and heterostructures. The central experiment combines a confocal laser scanning microscope with a scanning force microscope, which allows the spatially resolved measurement of electrostatic forces under local illumination of the nanostructure. On uncontacted hetero-nanosheets, both the potential profile across the heterointerfaces and the redistribution of photogenerated charge carriers will be quantitatively determined with high spatial resolution. Time-resolved measurements will also be developed here to directly follow the charging and discharging dynamics. On electrically contacted nanosheets, additional scanning photocurrent measurements will be combined with the electrostatic atomic force measurements to study the potential profile, especially at the contacts. These experiments will also be performed using focused X-rays from synchrotron radiation sources to significantly increase the spatial resolution of the photocurrent measurements and to combine them with versatile X-ray spectroscopy methods.

复杂的半导体/半导体异质纳米结构或金属/半导体混合结构在光电子学的各种应用中具有极大的兴趣。半导体异质结构可以通过跨异质界面分离光生电子-空穴对而用于光致发光。相反，注入异质结构的电荷载流子可以在界面区域复合，发光。金属/半导体混合结构理想地适用于MEMS，例如，通过将在半导体材料中光学产生的电子转移到附着的金属颗粒，其可以将质子还原为氢。本计画将发展各种二维异质及混合奈米结构的化学合成方法。通过一种半导体材料在另一种半导体材料上的受控外延生长，将合成SnSe/SnS核/壳纳米片，例如，其中可以经由阴离子变化选择性地调节价带边缘进展。此外，阳离子交换反应将用于从CuS纳米片开始合成Janus样CuS/CdS异质纳米片，其中导带能量以及因此电子定位通过阳离子梯度来控制。最后，金属纳米晶体在纳米片边缘上的定向生长应导致混合结构，其中光生电子位于边缘金属颗粒中，从而产生特别有效的光催化剂。除了纳米片的化学合成外，其光电性能的研究也是该项目的前景。这里的一个重要目标是直接遵循在单个混合和异质结构的光生载流子的本地化。中心实验结合了共聚焦激光扫描显微镜与扫描力显微镜，它允许在纳米结构的局部照明下的静电力的空间分辨测量。在未接触的异质纳米片上，异质界面上的电势分布和光生电荷载流子的再分布都将以高空间分辨率定量确定。这里还将开发时间分辨测量，以直接跟踪充电和放电动态。在电接触的纳米片上，额外的扫描光电流测量将与静电原子力测量相结合，以研究电势分布，特别是在接触处。这些实验还将使用来自同步辐射源的聚焦X射线进行，以显著提高光电流测量的空间分辨率，并将其与多功能X射线光谱学方法联合收割机相结合。