LEAPS-MPS: Nanopatterning Nitride Based Nanostructures Using Sequential Infiltration Synthesis for Optoelectronic Applications

该奖项全部或部分根据2021年美国救援计划法案（公法117-2）资助。光电器件，包括光电探测器、太阳能电池和发光二极管（LED），本质上是将光转换为电或将电转换为光的能量转换器件。这些器件用于现代生活的许多方面，如电信、能源、消费电子和固态照明。光电器件中最常见的活性材料是氮化镓（GaN）或氮化铝（AlN）。这些材料已经吸引了显著的注意力，并且由于它们在紫外（UV）和可见波长中的发射而引起极大的兴趣。氮化物材料的纳米结构并不像目前商业设备中使用的平面结构那样常见，但它们可以使未来的设备具有新的功能。有了LEAPS-MPS计划的这个奖项，伊利诺伊州立大学的研究人员通过使用一种称为顺序渗透合成（SIS）的合成方法开发了AlN和GaN的纳米材料。SIS允许他们研究氮化物材料的生长机制以及具有不同形状形貌的纳米结构的光学性质。除了这项研究对半导体行业非常感兴趣之外，该项目还增强了主要本科院校的本科教育，因为学生可以参与尖端的实验研究，这提供了动手合成和表征的机会。这一努力还通过将研究成果整合到物理课程中作为高级实验物理课程的一部分来扩大半导体劳动力。该奖项的获得者是一位早期职业女性教师，她是女性和少数民族学生的榜样，鼓励他们选择STEM职业。在光电子研究领域，III族氮化物如AlN和GaN由于其稳定性以及作为在紫外和可见光范围内发射的宽带隙半导体而在过去几十年中获得了极大的关注。目前用于商业器件的平面结构氮化物材料具有限制，例如由于与可用衬底的晶格失配而导致的缺陷和位错，这因此限制了所得器件的性能，高温要求限制了衬底的选择，并且尺寸不适合未来的纳米级器件。对于新兴器件，与平面结构相关的问题可以通过采用这些材料的纳米结构来缓解。然而，纳米结构氮化物材料的制造方法仍处于婴儿期，并且当前的方法是复杂的多步骤工艺。关于氮化物纳米结构的生长和随后的这些纳米结构的长距离图案化，需要显著的改进和基本的理解。凭借LEAPS-MPS计划的这一奖项，研究人员使用纳米结构嵌段共聚物（BCP）模板和称为顺序渗透合成（SIS）的无机沉积方法合成AlN和GaN纳米棒图案。SIS工艺涉及气相分子渗透到软聚合物材料中。本项目利用傅里叶变换红外光谱（FTIR）以及其他物理、结构和光学表征技术研究氮化物材料的SIS生长机制。这些和其他方法，包括扫描电子显微镜（SEM），能量色散X射线光谱（EDX），X射线衍射（XRD），光致发光（PL）和光致发光激发（PLE）光谱，和阴极发光（CL）成像，用于研究所得的纳米结构。这项工作开辟了新的研究途径，以实现氮化物纳米材料的生长和图案化使用SIS作为一种简便和具有成本效益的方法。该奖项反映了NSF的法定使命，并已被认为是值得通过评估使用基金会的知识价值和更广泛的影响审查标准的支持。

This award is funded in whole or in part under the American Rescue Plan Act of 2021 (Public Law 117-2). Non-Technical Summary:Optoelectronic devices, including photodetectors, solar cells, and light-emitting diodes (LEDs), are essentially energy conversion devices which converts light to electricity or vice versa. These devices are used in many aspects of modern life such as telecommunication, energy, consumer electronics, and solid-state lighting. Most commonly the active material in optoelectronic devices are Gallium Nitride (GaN) or Aluminum Nitride (AlN). These materials have attracted significant attention and are of great interest because of their emission in ultraviolet (UV) and visible wavelengths. Nanostructures of nitride materials are not as common as planar structures which are currently used in commercial devices, but they could enable future devices with novel functionalities. With this award from the LEAPS-MPS program researchers at Illinois State University develop nanopatterns of AlN and GaN by using a synthesis approach called Sequential Infiltration Synthesis (SIS). SIS allows them to investigate the growth mechanism of the nitride materials as well as optical properties of nanostructures with different shapes morphologies. In addition to this research being of great interest to the semiconductor industry, the project also enhances the undergraduate education at a primarily undergraduate institution because students can participate in cutting-edge experimental research, which provides hands-on synthesis and characterization opportunities. This effort also broadens the semiconductor workforce by integrating research results into the physics curriculum as part of an upper-level experimental physics courses. The recipient of this award, an early career female faculty member is a role model for female and minority students, encouraging them to choose STEM careers. Technical Summary:In the field of optoelectronic research, group III nitrides such as AlN and GaN have gained significant attention over last few decades due to their stabilities and as a wide band gap semiconductor with emission in the ultraviolet and visible ranges. The planar structured nitride materials currently used in commercial devices come with limitations such as defects and dislocations due to lattice mismatch with available substrates which consequently limit the performance of the resulting devices, high temperature requirements limiting choice of substrates and the dimensions are not suitable for futuristic nanoscale devices. For emerging devices, the concerns related to planar structures can be alleviated by employing nanostructures of these materials. However, fabrication methods of nanostructured nitride materials are still in infancy and current approaches are complex and multi-step processes. Significant improvements and a fundamental understanding are needed regarding the growth of nitride nanostructures and subsequent long-range patterning of these nanostructures. With this award from the LEAPS-MPS program the researchers synthesize AlN and GaN nanorod patterns using nanostructured block copolymer (BCP) templates and an inorganic deposition method called Sequential Infiltration Synthesis (SIS). The SIS process involves infiltration of gas phase molecules into soft polymeric materials. This project investigates the SIS growth mechanism for nitride materials using Fourier Transform Infrared Spectroscopy (FTIR) as well as other physical, structural and optical characterization techniques. These and other methods, including scanning electron microscopy (SEM), energy dispersive x-ray spectroscopy (EDX), X-ray diffraction (XRD), photoluminescence (PL) and photoluminescence excitation (PLE) spectroscopy, and cathodoluminescence (CL) imaging, are used to study the resulting nanostructures. The proposed work opens up new avenues of research to realize nitride nanomaterial growth and patterning using SIS as a facile and cost-effective method.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.