Diffusion of Guests, Dopants, and Impurity Atoms Through Open Cage Allotropes of Si and Related Structures

客体、掺杂剂和杂质原子通过硅及相关结构的开笼同素异形体的扩散

• 批准号: 1810463
• 负责人: Carolyn Koh
• 金额: $ 37.55万
• 依托单位: Colorado School of Mines
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2018
• 资助国家: 美国
• 起止时间: 2018-07-15 至 2023-06-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1810463&HistoricalAwards=false
• 关键词: Diffusion; Guests; Dopants; Impurity; Atoms

Non-technical Description: There is a great need for development of next generation materials, derived from earth abundant elements, that would revolutionize the electronics industry for future generations of devices including computer chips, lasers, and detectors. Silicon is the second most abundant element on the Earth's crust and the most technologically significant. Many exotic forms of silicon, which exhibit caged or tunnel crystalline structures, hold the promise of high efficiency and low cost disruptive electronic and photonic properties that would push silicon to a new level. These exotic silicon structures, however, tend to form around ionic guest atoms. Their potential can be only realized with complete ionic guest removal. This research project addresses this vital requirement by elucidating the fundamental diffusion and mobility pathways for guest ions in silicon caged/tunnel structures and unraveling the complexities of the mechanistic pathways to guest diffusion. The research will create a fundamental understanding of ionic motion in open silicon structures that has not been achieved to-date. Closely integrated with the research are strong education and outreach programs to provide significant training and mentoring opportunities for undergraduate, graduate and underrepresented groups in materials science, including summer workshops and internship programs for undergraduate and high school students, and community outreach. The team also collaborates with the Rocky Mountain Camp for Dyslexic Kids to provide summer camps developed for students with dyslexia who have interest in and aptitude for science, technology, engineering, and mathematics (STEM).Technical Description: Many exotic forms of earth abundant silicon are theoretically predicted to have properties, such as a direct bandgap, that would revolutionize electronics and photonics industries. This potential has not been realized and the key limitation is the critical requirement of complete removal of the guest atoms around which these open crystal structures form. The ultimate goal of this project is to elucidate the ionic and atomic diffusional pathways and mobility of alkali and alkaline earth ions, inert guest atoms, and dopants in silicon caged and tunnel structures. Although there have been a number of exotic forms of silicon investigated via theory, simulation, and small-scale synthesis, a fundamental knowledge of the guest diffusion/mobility mechanisms is severely lacking. The major barrier that prohibits guest diffusion/mobility studies is the inability to produce sufficient quantities of phase pure material in thin-film, powder and bulk form. This barrier can be overcome by synthesis approach undertaken by the research team, allowing the research to explore: which guest diffusion pathways are preferable, i.e., via small or large cages, five-fold or six-fold rings of cages; the role of non-idealities, like vacancies, or impurities, and how partial occupancy and ion-ion interaction create unusual diffusion/solubility kinetics; the effect of charged versus neutral species and electron donation on diffusion. The research efforts include: synthesis and development of thin films and powders (on the grams-scale) of phase pure silicon allotropes with well-defined diffusive properties; investigation of macroscopic diffusion through the crystalline lattice of thin films of silicon allotropes; exploring the guest location/environment and dynamics, the defect impurities, and intrinsic defects in both films and powders. Key techniques include: time-of-flight secondary ion mass spectroscopy, electron spin resonance, and solid-state nuclear magnetic resonance spectroscopy.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.

非技术描述：非常需要开发下一代材料，这些材料来自地球丰富的元素，这将彻底改变电子工业，用于未来几代设备，包括计算机芯片，激光器和探测器。硅是地壳中第二丰富的元素，也是技术上最重要的元素。许多奇异形式的硅，表现出笼状或隧道晶体结构，具有高效率和低成本的破坏性电子和光子特性，将把硅推向一个新的水平。然而，这些奇异的硅结构倾向于在离子客体原子周围形成。它们的潜力只能通过完全去除离子客体来实现。本研究项目通过阐明硅笼/隧道结构中客体离子的基本扩散和迁移途径，并揭示客体扩散机制途径的复杂性，解决了这一重要要求。这项研究将对迄今为止尚未实现的开放硅结构中的离子运动产生基本的理解。与研究紧密结合的是强大的教育和推广计划，为材料科学的本科生，研究生和代表性不足的群体提供重要的培训和指导机会，包括本科生和高中生的暑期研讨会和实习计划，以及社区推广。该团队还与Rocky Mountain Camp for Dyslexic Kids合作，为那些对科学、技术、工程和数学（STEM）感兴趣和有能力的阅读障碍学生提供夏令营。技术描述：理论上预测，地球上丰富的许多奇异形式的硅具有直接带隙等特性，这将彻底改变电子和光子学行业。这种潜力尚未实现，关键的限制是完全去除这些开放晶体结构形成的客体原子的关键要求。这个项目的最终目标是阐明离子和原子的扩散途径和流动性的碱金属和碱土金属离子，惰性客体原子，和掺杂剂在硅笼和隧道结构。虽然已经有一些外来形式的硅研究通过理论，模拟和小规模的合成，客体扩散/迁移率机制的基本知识是严重缺乏。阻止客体扩散/迁移率研究的主要障碍是无法产生足够量的薄膜、粉末和块状形式的相纯材料。这一障碍可以通过研究团队采用的合成方法来克服，从而使研究能够探索：哪些客体扩散途径是优选的，即，通过小或大的笼，笼的五重或六重环;非理想性的作用，如空位或杂质，以及部分占据和离子-离子相互作用如何产生不寻常的扩散/溶解动力学;带电与中性物质和电子捐赠对扩散的影响。研究工作包括：合成和发展的薄膜和粉末（克级）的相位纯硅同素异形体具有明确的扩散性能;宏观扩散通过硅同素异形体薄膜的晶格的调查;探索客户的位置/环境和动力学，缺陷杂质，和内在缺陷的薄膜和粉末。关键技术包括：该奖项反映了NSF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。

项目成果

Formation of Type II Silicon Clathrate with Lithium Guests through Thermal Diffusion

• DOI: 10.1021/acs.inorgchem.2c03703
• 发表时间: 2023-01-30
• 期刊: INORGANIC CHEMISTRY
• 影响因子: 4.6
• 作者: Liu，Yinan;Briggs，Joseph P.;Collins，Reuben T.
• 通讯作者: Collins，Reuben T.

Electron paramagnetic resonance study of type-II silicon clathrate with low sodium guest concentration

低钠客体浓度II型硅包合物的电子顺磁共振研究

• DOI: 10.1103/physrevb.101.245204
• 发表时间: 2020
• 期刊: Physical Review B
• 影响因子: 3.7
• 作者: Schenken, William K.;Liu, Yinan;Krishna, Lakshmi;Majid, Ahmad A.;Koh, Carolyn A.;Taylor, P. Craig;Collins, Reuben T.
• 通讯作者: Collins, Reuben T.

Synthesis and characterization of type II silicon clathrate films with low Na concentration

低Na浓度II型硅包合物薄膜的合成与表征

• DOI: 10.1063/5.0062723
• 发表时间: 2021
• 期刊: Applied Physics Reviews
• 影响因子: 15
• 作者: Liu, Yinan;Schenken, William K.;Krishna, Lakshmi;Majid, Ahmad A. A.;Furtak, Thomas E.;Walker, Michael;Koh, Carolyn A.;Taylor, P. Craig;Collins, Reuben T.
• 通讯作者: Collins, Reuben T.