Functionalizing LAyered 2D nanoflakes for Tailored optoelectronics

二维材料为纳米级光电子学提供了一个多功能的平台：不同的单原子厚度材料提供了各种各样的光学特性。这些材料支持的效应是独特的光学吸收，从微波到紫外线频率的光的转导或发射，通过超快门控控制电荷迁移率的能力，结合缺陷发射光子用于量子应用，或电子学的新机会。当不同的单层材料堆叠在一起，形成由设计控制性能的人工异质结构时，全新的潜力就会展现出来。例如，将石墨烯与六方氮化硼单层结合可以调节石墨烯的电子结构及其能带。异质结构结合不同的二维材料制成微尺度发光和光电子器件。双分子层过渡金属二硫族化合物中存在拓扑极化，双分子层中声子极化从双曲色散关系向非双曲色散关系转变。虽然已经探索了无限层的一些特性，但我们的项目探索了二维材料薄片和薄片异质结构的光电潜力。我们的工作的独特之处在于用紧密结合的方法来描述纳米结构中与量子限制相关的效应，并结合时间相关密度矩阵的描述。一个主方程解释了片状电子在外部光源或电门照射下的演化，包括电子-电子相互作用或缺陷的存在所产生的影响。我们将开发一个量子力学框架来模拟不同材料薄片在电磁照明下的电子动力学，并应用它来了解它们的光电特性。-扩展这个框架，以允许不同材料制成的元素堆叠。扩展的方法将应用于设计可调谐的电子特性和光学响应器件，例如电光调制器、极化电路或光学传感器。-对这些结构中的电子动力学及其在光学和光电子学中的应用进行全面研究。我们主要研究具有经典特性或量子统计特性的纳米片基发光器件。通过组合或旋转几个材料薄片，我们将设计这些光源的光谱特性及其方向性。我们将探索基于纳米片或纳米带的这种源的能量特性如何依赖于外部电门控，并利用这些信息进一步发展我们对小型化电光调制器的贡献。我们将研究在纳米可调谐隧道晶体管中，电子穿过纳米片或纳米带的绝缘势垒的隧穿。

2D materials provide a versatile playground for nanoscale optoelectronics: different single-atom thick materials offer a great variety of optical properties. Effects of interest supported by such materials are a unique optical absorption, the transduction or emission of light from microwave to ultraviolet frequencies, the ability to control the charge mobility by ultrafast gating, the incorporation of defects to emit photons for quantum applications, or novel opportunities for electronics.Whole new potentials unfolds when different monolayered materials are stacked, forming artificial heterostructures of properties controllable by design. For example, combining a graphene with a hexagonal boron nitride monolayer allows to modulate graphene's electronic structure and its energy band. Heterostructures combining different 2D materials make microscaled light emitting and optoelectronic devices. Topological polaritons occur in bilayer transition metal dichalcogenides and a transition from a hyperbolic to a non-hyperbolic dispersion relation for phonon polaritons occurs in twisted MoO3 bilayers.While some of these properties have been explored for infinite layers, our project explores the optoelectronic potential of 2D material flakes and flake-based heterostructures. Unique to our work is the description with a tight-binding methodology to accommodate effects related to the quantum confinement in the nanostructures, combined with a description in terms of time-dependent density matrix. A master equation accounts for the evolution of flake electrons upon illumination with external light sources or electric gating, including effects resulting from electron-electron interactions or presence of defects. We will-develop a quantum-mechanical framework to model electron dynamics under electromagnetic illumination in different material flakes and apply it to understand their optoelectronic properties at the fundamental level.-extend this framework to allow stacking of elements made of different materials. The extended method will be applied to design devices of tunable electronic properties and optical response, e.g. electro-optic modulators, polaritonic circuits, or optical sensors.-perform a comprehensive study of electron dynamics in these structures and their applications for optics and optoelectronics.The applications we concentrate on are nanoflake-based light emitting devices with classical characteristics or with quantum statistics. By combining or rotating several material flakes we will engineer the spectral properties of these sources and their directionality. We will explore how the energy characteristics of such sources based on nanoflakes or ribbons rely on external electric gating, and exploit that information to develop our contribution further towards miniaturized electro-optic modulators. We will study the electron tunnelling through insulating barriers in nanoflakes or ribbons for nanoscaled tunable tunnel transistors.