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

非技术：硅电子面临技术瓶颈，即使有需要的设备运行在不断增加的速度。太赫兹（THz）技术被视为这个问题的潜在解决方案，因为它将使设备的运行速度达到100 GHz到10,000 GHz，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系列，有机-无机杂化卤化铅钙钛矿来制造有源太赫兹器件。近来，钙钛矿因其在高性能太阳能电池方面的潜力而备受关注。钙钛矿的基本性质使它们对太阳能电池具有吸引力，也使它们对太赫兹应用具有吸引力。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而发生化学改变。钙钛矿也很容易加工。高质量的钙钛矿薄膜可以很容易地沉积通过一个简单的自旋镀膜工艺，通常用于半导体加工工业。不同的钙钛矿具有不同的光学和电子特性，可以很容易地堆积在一起。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。这种易于制造的特性使得新器件的性能在只使用一种半导体时是不可能实现的。PI将通过犹他州科学奥林匹克竞赛等经验，努力扩大科学教育的参与。PI将为高中教师开设课程，让本科生和高中生参与研究，并与盐湖城山谷的第一代学生接触。技术：提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）器件。这些半导体虽然在光伏应用中得到了很好的研究，但在太赫兹应用中几乎完全没有被探索过。它们对于太赫兹应用非常有吸引力，因为它们的光学特性可以相对容易地进行化学工程。由于它们可以溶液处理，多个钙钛矿可以浇铸并以极高的精度相互靠近，而不会对材料响应产生任何影响。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，同时沉积和定义额外的层，从而使这些半导体具有微米级精度的图案。通过这样做，我们希望创造出有源太赫兹器件，这些器件具有仅使用单一半导体（如硅或砷化镓）无法实现的功能。具体来说，我们打算演示(i)超快太赫兹频率敏捷器件，（ii）使用二维钙钛矿的电光器件，其中施加的（太赫兹）电场可以在多量子阱结构中诱导斯塔克效应或量子受限斯塔克效应，以及（iii）基于表现出光学波长敏感控制的场效应晶体管太赫兹特性。这项提议的研究提供了变革性的能力，因为在一个设备中使用多个钙钛矿在技术上具有挑战性，无法使用传统的半导体来实现。该奖项反映了美国国家科学基金会的法定使命，并通过使用基金会的知识价值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.