Two-Stage Buffer Layers for Solar Power in a InGaP - Si Double Junction Cell

摘要：本课题的目标是在硅片衬底上采用薄的Ge成核层，然后采用由阶跃渐变的InxGa1-xP组成的变质缓冲层，实现In0.50Ga0.50P的单片集成。薄的3ml Ge层将为阶梯渐变InxGa1-xP提供成核模板，并在Si底p-n结的顶部表面提供相干的伪晶界面。我们将能够一起解决两个关键的材料科学问题？(i)为通常不能与Si原子直接界面的III-P半导体提供成核；（ii）提供一个干净的界面层，可以电钝化Si底部p-n结的n型Si发射极层。更广泛的影响美国国家工程院选出了21世纪全球人类面临的14大工程挑战。挑战1：“让太阳能变得更经济？”由吗?克服普及太阳能发电的障碍。”我们的项目提供了一种解决这一社会重大挑战的方法，通过展示一种两阶段变质缓冲，设计成单片集成In0.50Ga0.50P和Si，尽管晶格不匹配，成为一种高效，经济且无毒的太阳能电池。两名研究生将从事半导体材料表征和外延薄膜合成。此外，我们将从当地独立学区选择一名K-12教师参加为期6周的暑期课程。这个项目的重点是让教师参与到我们的研究中，并为未来的科学家、工程师和技术人员提供后续的教学材料。

AbstractIntellectual MeritThe objective of this project is to monolithically integrate In0.50Ga0.50P on Si wafer substrates by using a thin nucleation layer of Ge followed by a metamorphic buffer comprised of step-graded InxGa1-xP. The thin 3 ML Ge layer will provide a nucleation template for the step-graded InxGa1-xP as well as provide a coherent, pseudomorphic interface at the top surface of the Si bottom p-n junction. We will be able to solve two key materials science issues together ? (i) provide nucleation for III-P semiconductors that normally do not interface well directly with Si atoms and (ii) provide a clean interfacial layer that can electrically passivate the n-type Si emitter layer of the Si bottom p-n junction. Broader ImpactThe National Academy of Engineering selected the top 14 engineering challenges for the 21st century facing humanity worldwide. Challenge #1 - "Make Solar Energy Economical? by ?overcoming the barriers to widespread solar power generation." Our project provides a way to address this societal grand challenge by demonstrating a two stage metamorphic buffer designed to monolithically integrate In0.50Ga0.50P and Si, despite lattice mismatch, into an efficient, affordable and nontoxic solar cell. Two graduate students will be engaged in semiconductor material characterization and epitaxial thin film synthesis. In addition, we will select a K-12 teacher from a local Independent School District to participate in a 6-week summer program. This program will focus on engaging the teacher with our research and the subsequent development of classroom materials for teaching future scientists, engineers, and technologists.