Collaborative Research: DMREF: Quasi-Direct Semiconductors

合作研究：DMREF：准直接半导体

基本信息

批准号：
2119555
负责人：
Feliciano Giustino
金额：
$ 77.48万
依托单位：
University of Texas at Austin
依托单位国家：
美国
项目类别：
Standard Grant
财政年份：
2021
资助国家：
美国
起止时间：
2021-10-01 至 2025-09-30
项目状态：
未结题

来源：
https://www.nsf.gov/awardsearch/showAward?AWD_ID=2119555&HistoricalAwards=false
关键词：
Collaborative Research DMREF Quasi Direct

项目摘要

Nontechnical DescriptionThe rapid identification of materials and structures with properties tailored to specific applications is a fundamental aspect of the Materials Genome Initiative. A basic prerequisite for the success of the Initiative is the ability to predict the targeted properties starting from basic information about the atomic composition and configurations in the material. For devices such as solar cells, detectors, light-emitting diodes, and lasers, the key design consideration is the fraction of the incident light energy absorbed at any particular wavelength. This DMREF project focuses on a particular class of materials, dubbed “quasi-direct” semiconductors, for which a satisfactory theory of light absorption does not exist. The project will develop the theoretical tools needed for the calculation of optical absorption in quasi-direct semiconductors and validate the new theoretical methods by carrying out optical experiments in structures optimized for the accurate measurement of the absorption coefficient. More than 200 quasi-direct semiconductors have already been identified in the Materials Project database, and this project will make it possible to incorporate such materials as optical components of future devices. All codes released will be open source to maximize societal impact, and the semiconductor industry will also benefit from the highly trained STEM workforce delivered by the project. A strong educational focus will be placed on undergraduate students by partnering with the Arizona State University (ASU) Sundial Project, which recruits and mentors students who traditionally have limited access to STEM careers. At the University of Texas at Austin (UT Austin), undergraduates will be directly involved in the development of the new codes. Technical DescriptionIn quasi-direct semiconductors, the energy threshold for vibration-assisted light absorption (the so-called indirect gap) is only slightly below the energy threshold for direct light absorption (the direct gap). Because of this proximity, the quantum-mechanical second-order perturbation theory expressions for vibrational-assisted absorption diverge as the photon energy approaches the direct gap, leading to unphysical predictions. The proposed solutions include the development of many-body quasi-degenerate perturbation theory and the use of a non-perturbative special displacement method by the team at UT Austin. The experimental validation requires special samples and materials, since the absorption coefficient must be determined with high accuracy over a spectral range where it changes by orders of magnitude. The needed samples will be fabricated at ASU using custom Chemical Vapor Deposition methods, and the optical measurements will also be performed by the ASU team.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.

非技术描述的材料和结构的快速识别具有针对特定应用的特性的材料和结构是材料基因组计划的一个基本方面。该计划成功的基本先决条件是能够从有关原子成分和材料中的原子成分和配置开始的目标属性。对于诸如太阳能电池，探测器，发光二极管和激光器等设备，关键的设计考虑因素是在任何特定波长下吸收的入射光能的比例。该DMREF项目的重点是一种被称为“准直接”半导体的特定材料，为此不存在令人满意的光损失理论。该项目将开发用于计算准直接半导体光损耗所需的理论工具，并通过在优化的结构中进行光学实验来验证新的理论方法，以测量吸收系数的准确性测量。在材料项目数据库中已经确定了200多个准直接半导体，并且该项目将有可能纳入诸如未来设备的光学组件之类的材料。所有发布的代码将是最大化社会影响的开源，半导体行业还将受益于该项目提供的训练有素的STEM劳动力。通过与亚利桑那州立大学（ASU）Sundial Project合作，将向本科生提供强大的教育重点，该项目的报告和指导的学生传统上获得了STEM职业的机会有限。在德克萨斯大学奥斯汀分校（UT奥斯汀），本科生将直接参与新法规的开发。技术描述在准直接的半导体中，振动辅助光滥用的能量阈值（所谓的间接间隙）仅略低于直接光抽象的能量阈值（直接差距）。由于这种接近度，随着光子能量接近直接间隙，振动辅助抽象的量子二阶扰动理论表达式散开，从而导致非物理预测。拟议的解决方案包括开发多体准脱位扰动理论以及UT Austin团队的非扰动特殊位移方法的使用。实验验证需要特殊的样品和材料，因为必须在光谱范围内以高度准确性确定吸收系数，在该光谱范围内它随数量级变化而变化。所需的样品将使用自定义化学蒸气沉积方法在ASU制造，并且光学测量还将由ASU团队执行。该奖项反映了NSF的法定任务，并认为值得通过基金会的知识分子优点和更广泛的影响审查标准通过评估来进行评估。