Collaborative Proposal: Low-Cost Substrates for III-V Photovoltaics by Self-Templated Selective Epitaxial Growth of Germanium on Silicon

“这项奖励是根据2009年美国复苏和再投资法案（公法111-5）资助的。”技术。该项目致力于在硅衬底上外延生长高质量的单晶锗。该方法是通过分子束外延（MBE）在Si上进行Ge的选择性外延生长（SEG），以使Ge覆盖层与Si衬底之间的接触面积/应力最小。这个想法是采用一个穿孔的夹层，通过这个夹层，外延粘附的锗岛生长并随后合并形成一个连续的薄膜。SEG过程在概念上是建立良好的，但在孤岛聚结过程中存在缺陷形成，这是本文从实验和理论/模拟角度讨论的主题。该项目涉及协作实验和计算工作，利用非常高分辨率的显微镜功能直接连接实验和原子模拟。原子分解实验研究序列将结合大规模分子动力学和基于最先进技术的动力学蒙特卡罗模拟。目的是描绘整个SEG过程的各种现象学组成部分，以便建立一个完整的机制图像。目标包括：(1)对自模板SEG的定量预测原子尺度理解和优化这种能力的方法；(2)分析在SEG以外的各种异质外延应用中具有广泛重要性的几个基本原子过程。非技术。本项目旨在解决电子/光子材料科学中具有技术相关性的主题领域的基础研究问题。降低与锗基板相关的成本障碍是使先进的III-V型光伏发电成为经济上可行的发电选择的关键因素。这种成本的降低可能会使太阳能的使用范围比现在更广泛。在这一合作过程中，新墨西哥大学将受益于宾夕法尼亚大学的计算能力，而宾夕法尼亚大学将受益于新墨西哥大学？S纳米制造、生长和分析能力。合作的努力将包括主要研究人员和研究生对合作机构的频繁访问。该研究项目还将为每个机构的研究生和本科生提供跨学科的教育环境。除了研究教育外，pi还将为半导体材料科学与工程的实验和计算工具课程开发材料，该课程将在新墨西哥大学和宾夕法尼亚大学同时教授。pi将利用新墨西哥大学和宾夕法尼亚大学的一些外展项目，积极教育未来的学生关于研究型教育机会。这些外展项目在提高少数民族学生和妇女的入学率方面具有巨大的潜力。该项目还加强了NSF EPSCoR在新墨西哥州纳米材料方面的倡议。

'This award is funded under the American Recovery and Reinvestment Act of 2009 (Public Law 111-5).' Technical. This project addresses epitaxial growth of high quality, single-crystalline Ge on Si substrates. The approach is selective epitaxial growth (SEG) of Ge on Si by molecular beam epitaxy (MBE) conducted in a way so as to minimize the contact area/stress between the Ge overlayer and the Si substrate. The idea is to employ a perforated interlayer, through which epitaxially adhered Ge islands grow and subsequently coalesce to form a continuous film. The SEG process is well established in concept but suffers from defect formation during island coalescence, which is a topic addressed here from both experimental and theory/simulation perspectives. The project involves collaborative experimental and computational work that takes advantage of very high resolution microscopy capabilities for direct connections between experiments and atomistic simulations. Sequences of atomically resolved experimental studies will be combined with large scale molecular dynamics and kinetic Monte Carlo simulations based on state-of-the-art techniques. The aim is to delineate various phenomenological components of the overall SEG process in order to build a complete mechanistic picture. Goals include: (1) a quantitatively predictive atomistic-scale understanding of self-templated SEG and a way to optimize this capability, and (2) an analysis of several basic atomistic processes that have broad importance in a variety of heteroepitaxy applications beyond SEG. Non-Technical. The project addresses fundamental research issues in a topical area of electronic/photonic materials science having technological relevance. Lowering the cost barrier associated with Ge substrates is a key element in making advanced III-V photovoltaics as an economically viable option to generate electricity. This cost reduction may transformatively enable much wider use of solar energy than what is possible today. During the course of this collaborative effort, UNM will benefit from the computational capability at Penn, while Penn will benefit from UNM?s nanofabrication, growth, and analytic capabilities. The collaborative efforts will include frequent visits by the principal investigators (PIs) and graduate students to partner institutions. The research project also will offer an interdisciplinary educational environment for mentoring graduate and undergraduate students at each institution. In addition to research education, the PIs will develop materials for a course in Experimental and Computational Tools in Semiconductor Materials Science and Engineering, which will be taught simultaneously at UNM and Penn. The PIs will utilize a number of outreach programs at UNM and Penn to actively educate prospective students about research-oriented educational opportunities. These outreach programs have significant potential to improve the enrollment of minority students and women. This project also enhances the NSF EPSCoR initiative in nanomaterials in New Mexico.