Novel Functional Materials - An Optical Perspective

新型功能材料——光学视角

• 批准号: RGPIN-2022-05214
• 负责人: Reedyk, Maureen
• 金额: $ 1.75万
• 依托单位: Brock University
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2022
• 资助国家: 加拿大
• 起止时间: 2022-01-01 至 2023-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=762563
• 关键词: Novel; Functional; Materials; Optical; Perspective

Materials science is built on the discovery and manipulation of novel materials with functional characteristics such as energy conversion and storage, charge--spin coupling, and  multi-ferroicity. These properties can be exploited in photovoltaic, optoelectronic and spintronic devices. The discovery of graphene and its exceptional multi-functionality arising from its high mechanical strength, excellent heat and electrical conductivity, and optical transparency has re--ignited interest in other two dimensional materials such as layered oxides, chalcogenides, and van der Waals coupled compounds. As part of a research program established to study the optical properties of quantum materials we propose to synthesize and investigate the structural, thermal, electrical, magnetic, and optical properties of low dimensional functional materials. We have chosen to focus on several novel materials which include: (1) 2D layered chalcogenides (i) beta--As2Te3, which is structurally identical to topological insulator Bi2Te3, and (ii) misfit (PbSe)-(-NbSe2),  where incommensurability between layers could lead to unique applications, (2) thin films of DyCrO3 with multiferroic behaviour,  and (3) 2D-layered Halide double perovskite (BA)2CsAgBiBr7 (BA=n-butylammonium), whose 3D variant Cs2AgBiBr6  has photovoltaic functionality and exhibits several as yet not understood phase transitions. Our strategy is to manipulate the properties via doping and intercalation in order to characterize and study their evolution towards eventual tailoring to applications. Our main emphasis will be on their response to light with other properties evaluated for characterization purposes. Materials within the chalcogenide family typically have gapped ground states such as superconductivity or a charge density wave. The investigation of the optical properties in these states is exacting because it must be conducted at experimentally challenging low temperatures and energies. Our optical apparatus is uniquely set up to handle this. We intend to further extend the capabilities of our system to perform measurements in the presence of a magnetic field since we intend to investigate the magneto--optical properties of DyCrO3 and to introduce magnetic doping in the 2D layered materials we are investigating. We also plan to increase the spectral wavelength range that we can measure at very low temperature by using filters that we create by electro-chemically etching silicon to make it porous. The filters work by scattering light of wavelengths shorter than the pore dimension. By varying the silicon doping, orientation and parameters of the etching process we can change the size of the pores which changes the cutoff wavelength of the filter. By varying current as a function of time we can produce porous silicon multi-layer devices such as  Bragg reflectors and micro-cavities with applications in sensors to detect solvents, pesticides, and biological material.

材料科学是建立在发现和操纵具有能量转换和存储、电荷-自旋耦合和多铁性等功能特征的新材料的基础上的。这些特性可用于光伏、光电和自旋电子器件。石墨烯的发现及其高机械强度、优异的导热性和导电性以及光学透明性所带来的特殊多功能，重新点燃了人们对其他二维材料的兴趣，如层状氧化物、硫族化合物和范德华偶联化合物。作为研究量子材料光学性质的研究项目的一部分，我们建议合成和研究低维功能材料的结构、热、电、磁和光学性质。我们选择了几种新颖的材料，包括：(1) 2D层状硫族化合物(i) β -As2Te3，其结构与拓扑绝缘体Bi2Te3相同，（ii） misfit (PbSe)-(- nbse2)，其中层间的不可通约性可能导致独特的应用，(2)具有多铁性行为的DyCrO3薄膜，以及(3)2D层状卤化物双钙钛矿（BA）2CsAgBiBr7 （BA=n-丁铵），其3D变体Cs2AgBiBr6具有光伏功能，并表现出几种尚未理解的相变。我们的策略是通过掺杂和插层来控制这些性质，以表征和研究它们的演变，最终适应应用。我们的主要重点将是它们对光的反应，以及为表征目的而评估的其他性质。硫族材料通常具有间隙基态，如超导性或电荷密度波。对这些状态的光学性质的研究是严格的，因为它必须在实验上具有挑战性的低温和低能量下进行。我们的光学仪器是专门用来处理这个问题的。我们打算进一步扩展我们的系统在磁场存在下进行测量的能力，因为我们打算研究DyCrO3的磁光学特性，并在我们正在研究的二维层状材料中引入磁掺杂。我们还计划增加光谱波长范围，我们可以在非常低的温度下测量，通过使用我们通过电化学蚀刻硅来制造的过滤器，使其多孔。滤光片的工作原理是散射波长比孔隙尺寸短的光。通过改变硅掺杂、取向和蚀刻工艺参数，可以改变孔的大小，从而改变滤光片的截止波长。通过改变电流作为时间的函数，我们可以生产多孔硅多层器件，如布拉格反射器和微腔，应用于检测溶剂，农药和生物材料的传感器。