Hybrid Organic-Inorganic Lead-Halide Perovskite-Based Active Terahertz Devices

非技术：硅电子产品面临着技术瓶颈，尽管人们需要以不断提高的速度运行的设备。太赫兹(THz)技术被视为这一问题的潜在解决方案，因为它将使设备能够以100 GHz到10,000 GHz的速度运行，远远快于传统电子设备。该项目将使用一种相对较新的半导体家族--有机-无机混合卤化铅钙钛矿来制造有源太赫兹设备。钙钛矿材料由于其在高性能太阳能电池中的潜力，最近受到了极大的关注。钙钛矿的基本性质使其对太阳能电池具有吸引力，也使其在太赫兹应用中具有吸引力。例如，钙钛矿对光的反应可以通过改变分子中的卤化物基团来改变。钙钛矿也很容易加工。高质量的钙钛矿薄膜可以很容易地通过简单的旋涂工艺沉积，这是半导体加工业中常用的方法。具有不同光学和电学性质的不同钙钛矿可以很容易地彼此相邻沉积。相比之下，传统的无机半导体，如硅和砷化镓，很难做到这一点。这种制造的简单性允许新的器件能力，当只使用一种类型的半导体时，这些能力是根本不可能实现的。国际科学协会将通过犹他州科学奥林匹克竞赛等经验，努力扩大对科学教育的参与。PI将为高中教师开发课程，让本科生和高中生参与研究，并与盐湖流域的第一代学生接触。技术：拟议的工作旨在开发一种基于有机-无机卤化铅钙钛矿的新型太赫兹(THz)设备。虽然这些半导体在光伏应用方面得到了很好的检验，但在太赫兹应用方面几乎完全没有人探索过。它们对太赫兹的应用非常有吸引力，因为它们的光学性质可以相对容易地进行化学工程设计。由于它们可以被溶液处理，多个钙钛矿可以在彼此紧密接近的情况下以极高的精度铸造和描绘，而不会对材料的响应产生任何影响。我们打算开发一种独特的制造技术，使用聚合物分层工艺来保护沉积的钙钛矿层，同时沉积和定义更多的层，从而以微米级的精度制作这些半导体的图案化。通过这样做，我们希望创造出具有仅使用单一半导体(如硅或砷化镓)无法实现的功能的有源太赫兹器件。具体地说，我们打算展示(I)超快太赫兹频率捷变器件，(Ii)使用2D钙钛矿结构的电光器件，其中外加(THz)电场可以在多量子阱结构中诱导斯塔克效应或量子限制斯塔克效应，以及(Iii)基于具有光学波长敏感控制太赫兹特性的场效应晶体管。这项拟议的研究提供了变革性的能力，因为在这里提出的在单个设备中使用多个钙钛矿材料在使用传统半导体实现的技术上具有挑战性。该奖项反映了NSF的法定使命，并通过使用基金会的智力优势和更广泛的影响审查标准进行评估，被认为值得支持。

Non-technical:Silicon electronics face a technological bottleneck even as there is a need for devices that operate at ever increasing speeds. Terahertz (THz) technology is viewed as a potential solution to this problem as it will enable devices that operate at speeds of 100 GHz to 10,000 GHz, far faster than conventional electronics. The project will create active THz devices using a relatively new family of semiconductors, organic-inorganic hybrid lead halide perovskites. Perovskites have recently gained significant attention because of their potential for high-performance solar cells. The basic properties of perovskites that make them attractive for solar cells also make them appealing for THz applications. For example, the response of perovskites to light can be altered chemically by changing the halide group in the molecule. Perovskites are also easy to process. High quality thin films of perovskites can be readily deposited via a simple spin coating process that is routinely used in the semiconductor processing industry. Different perovskites with distinct optical and electronic properties can be easily deposited next to one another. In contrast, this is difficult to do with conventional inorganic semiconductors, such as silicon and gallium arsenide. This ease of fabrication allows for new device capabilities that are simply not possible when only one type of semiconductor is used. The PI will work to broaden participation in science education through experiences such as the Utah Science Olympiad. The PI will develop classes for high school teachers, involve undergraduate and high school students in research, and engage with first generation students in the Salt Lake Valley.Technical:The proposed work intends to develop a new class of terahertz (THz) devices based on organic-inorganic lead halide perovskites. These semiconductors, while well examined for photovoltaic applications, have been almost completely unexplored for THz applications. They are extremely attractive for THz applications because their optical properties can be chemically engineered with relative ease. Since they can be solution processed, multiple perovskites can be cast and delineated with extremely high precision in close proximity to one another, without any degradation to the material response. We intend to develop a unique fabrication technique that allows for patterning of these semiconductors with um-scale precision using a polymer delamination process that protects the deposited perovskite layers, while additional layers are deposited and defined. By doing so, we expect to create active THz devices that exhibit functionality that is not possible using only a single semiconductor, such as silicon or gallium arsenide. Specifically, we intend to demonstrate (i) ultrafast THz frequency agile devices, (ii) electro-optic devices using 2D perovskites, where the applied (THz) electric field can induce the Stark effect or quantum confined Stark effect in the multiple quantum well structures, and (iii) field effect transistors based that exhibit optical wavelength sensitive control of the THz properties. The proposed research offers transformative capabilities because the use of multiple perovskites within a single device proposed here is technically challenging to achieve using conventional semiconductors.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.