Modification of Soft Inorganic Thin Films through the use of van der Waals Epitaxial Strain

通过使用范德华外延应变对软无机薄膜进行改性

• 批准号: 1635520
• 负责人: Jian Shi
• 金额: $ 37.92万
• 依托单位: Rensselaer Polytechnic Institute
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2016
• 资助国家: 美国
• 起止时间: 2016-09-01 至 2019-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1635520&HistoricalAwards=false
• 关键词: Modification; Soft; Inorganic; Thin; Films

Human society's consistent pursuit of better means of information communication and effective use of it?s energy supplies, requires continual innovation in the underlying technological materials infrastructure. Transformative technologies rely on breakthroughs in their scientific foundations, such as materials and processing. Recently, a number of soft inorganic solids have shown potential for applications in energy conversion and information manipulation, and promising new insight into the physics of exotic states of matter. Theoretical works suggest that reversible mechanical deformations in these materials could lead to either gradual or abrupt shifts of their physical properties. However, these soft materials, particularly, heavy halides and chalcogenides, experience difficulty in utilizing conventional chemical approaches to induce for deformation purpose due to their unique materials structures and atomic arrangement. This work addresses this problem by exploring the possibility of stretching soft but heavy halide and chalcogenide materials through van der Waals epitaxy. The research will introduce a new set of useful optoelectronic, electro-optic, logic and memory materials in the form of strained thin films. Researchers will also pursue educational goals by establishing a 'Graphics for Learning' program, which will train engineering undergraduate students, especially from underrepresented groups, through the graphical presentation of information. Strain within epitaxial electronic and optical materials has been used to produce desirable materials properties unachievable in the unstrained state. While used to great effect in conventional semiconductors, the introduction of strain into the class of van der Waals bonded compounds has been difficult. The van der Waals compounds formed from elements deeper in the periodic table, termed heavy halides and chalcogenides, may offer new opportunity to strain-modify these materials. This grant looks to synthesize 'soft' and 'heavy' materials as thin films out of the heavier elements via van der Waals epitaxy onto useful substrates under conditions that lead to significant elastic strains within the epitaxial layers. The focus will be on two model materials: the van der Waals solid PbI2 and non-van der Waals solid CH3NH3PbCl3. Several other materials including CdTe, CdS, SbI3 and Sb2S3 will also be studied. The strain magnitude, strain relaxation mechanisms and strain-induced physical properties will be characterized by X-ray diffraction, Raman spectroscopy, transmission electron microscopy and angle-resolved photoluminescence spectroscopy. First-principle calculations will be employed to elucidate the experimental observations. After establishing a van der Waals nucleation/growth model for halides and chalcogenides, modifications to the synthesis of these epitaxial materials will be directed at achieving elastic strain engineering via the van der Waals epitaxial process. The magnitude and anisotropy of the epitaxial strain and the effect on materials properties will be used to develop a mechanistic understanding of the underlying changes in and behavior of the epitaxial 'heavy' van der Waals materials.

人类社会对更好的信息通信手段和有效利用能源供应的一贯追求，需要底层技术材料基础设施的不断创新。变革性技术依赖于材料和加工等科学基础的突破。最近，许多软无机固体显示出在能量转换和信息操纵方面的应用潜力，并有望为奇异物质态的物理学提供新的见解。理论工作表明，这些材料的可逆机械变形可能导致其物理性能逐渐或突然发生变化。然而，这些软材料，特别是重卤化物和硫属化物，由于其独特的材料结构和原子排列，在利用传统的化学方法诱导变形目的时遇到困难。这项工作通过探索通过范德华外延拉伸柔软但重的卤化物和硫族化物材料的可能性来解决这个问题。该研究将引入一组新的有用的应变薄膜形式的光电、电光、逻辑和存储材料。研究人员还将通过建立“图形学习”计划来实现教育目标，该计划将通过信息的图形呈现来培训工程本科生，特别是来自代表性不足群体的学生。 外延电子和光学材料内的应变已被用来产生在无应变状态下无法实现的所需材料性能。虽然在传统半导体中的应用非常有效，但将应变引入范德华键合化合物类中一直很困难。由元素周期表中较深的元素形成的范德华化合物，称为重卤化物和硫族化物，可能为应变改性这些材料提供新的机会。该资助旨在通过范德华外延将较重元素合成“软”和“重”材料作为薄膜，并在外延层内产生显着弹性应变的条件下将其合成到有用的基板上。重点将放在两种模型材料上：范德华固体 PbI2 和非范德华固体 CH3NH3PbCl3。还将研究其他几种材料，包括 CdTe、CdS、SbI3 和 Sb2S3。应变大小、应变松弛机制和应变引起的物理性质将通过 X 射线衍射、拉曼光谱、透射电子显微镜和角分辨光致发光光谱进行表征。将采用第一原理计算来阐明实验观察结果。在建立卤化物和硫属化物的范德华成核/生长模型后，对这些外延材料的合成进行修改将旨在通过范德华外延过程实现弹性应变工程。外延应变的大小和各向异性以及对材料性能的影响将用于发展对外延“重”范德华材料的潜在变化和行为的机械理解。

项目成果

Effect of strain on the Curie temperature and band structure of low-dimensional SbSI

应变对低维SbSI居里温度和能带结构的影响

• DOI: 10.1063/1.5017490
• 发表时间: 2018
• 期刊: Applied Physics Letters
• 影响因子: 4
• 作者: Wang, Yiping;Hu, Yang;Chen, Zhizhong;Guo, Yuwei;Wang, Dong;Wertz, Esther A.;Shi, Jian
• 通讯作者: Shi, Jian

Van Der Waals Hybrid Perovskite of High Optical Quality by Chemical Vapor Deposition

• DOI: 10.1002/adom.201700373
• 发表时间: 2017-11-02
• 期刊: ADVANCED OPTICAL MATERIALS
• 影响因子: 9
• 作者: Chen, Zhizhong;Wang, Yiping;Shi, Jian
• 通讯作者: Shi, Jian

van der Waals epitaxy of CdTe thin film on graphene

• DOI: 10.1063/1.4964127
• 发表时间: 2016-10
• 期刊: Applied Physics Letters
• 影响因子: 4
• 作者: D. Mohanty;W. Xie;Yiping Wang;Zonghuan Lu;Jian Shi;Shengbai Zhang;Gwo-Ching Wang;T. Lu;I. Bhat

Surface and interface of epitaxial CdTe film on CdS buffered van der Waals mica substrate

• DOI: 10.1016/j.apsusc.2017.03.260
• 发表时间: 2017-08
• 期刊: Applied Surface Science
• 影响因子: 6.7
• 作者: Y. -. Yang;Lucas J. Seewald;D. Mohanty;Yiping Wang;L. H. Zhang;K. Kisslinger;W. Xie;Jian Shi;I. Bhat;Shengbai Zhang;T. Lu;Gwo-Ching Wang

van der Waals epitaxial ZnTe thin film on single-crystalline graphene

• DOI: 10.1063/1.5011941
• 发表时间: 2018-01
• 期刊: Journal of Applied Physics
• 影响因子: 3.2
• 作者: Xin Sun;Zhizhong Chen;Yiping Wang;Zonghuan Lu;Jian Shi;Morris Washington;T. Lu