Rational Engineering of Semiconductor Nanowire Crystal Structure for Next Generation Energy Conversion Devices

提案编号：1133563 PI：Filler，Michael A.智力优势：这项NSF提案的首要研究目标是测试以下假设：在生长过程中精确控制纳米线表面化学可以实现半导体纳米线晶体结构的合理工程。这一假设的成功验证将改善制造高效的基于硅基的光伏和热电能量转换器件的前景。与主导该领域的试错方法相反，在这些研究期间，将利用定制的原位红外光谱实验平台从根本上询问控制自下而上半导体纳米线合成和结构的化学。真空生长环境和原位测量的组合在其限制纳米线降解和获得先前无法实现的化学细节水平的能力方面具有变革性。这将是可能的，清楚地区分哪些表面物种或表面物种的组合，以及什么特定的键合结构，最强烈地影响纳米线结构。硅纳米线作为一个技术相关的模型系统，将是这项工作的重点，但关键的发现将广泛适用于一系列重要的半导体纳米材料。具体目标有三个方面：（1）确定表面结合氢对纳米线晶体取向的作用，（2）通过生长过程中纳米线侧壁的有机功能化来控制纳米线晶体结构，以及（3）调节作为轴向位置的函数的纳米线结构以产生新颖的超结构。这些目标的结果将共同作为半导体纳米线化学结构和结构性质关系的基础，这些关系对于实现具有先进性能的器件至关重要。初步数据已经证明了纳米线生长过程中表面化学的重要性，并为开始这项研究工作提供了坚实的基础。更广泛的影响：突破性的光伏和热电技术可以广泛应用，可以改变我们的能源系统，减少碳足迹。在这项工作中获得的洞察力将大大加快下一代设备的纳米级组件的设计，为美国宣布的未来几年减少碳排放的目标做出重大贡献。虽然这项工作将集中在能量转换上，但预计这些进展将在包括光子学、电子学、量子计算和电化学在内的一系列领域具有广泛的适用性。此外，各级STEM教育的学生以及公众将准备好明智地讨论和浏览新兴的可再生能源景观。利用因特网和社交网络工具将直接把关键的外联工作纳入广泛的多学科受众的日常活动。特别是，Solar教授的博客将被用来通过以教育和娱乐方式利用日常经验的形式制作的短视频短片传播最新的科学和技术进展。PI还参与当地的外联活动，重点是在K-12级代表性不足的少数民族学生。这些努力将通过演讲活动和动手科学演示继续和扩大。此外，格鲁吉亚理工学院的本科生将有机会参加研究实习。

Proposal Number: 1133563PI: Filler, Michael A. Intellectual Merit: The overarching research objective of this NSF proposal is to test the hypothesis that precise control of nanowire surface chemistry during growth can enable the rational engineering of semiconductor nanowire crystal structure. Successful validation of this hypothesis would improve the prospects for fabricating highly efficient nanowire-based photovoltaic and thermoelectric energy conversion devices. As opposed to the trial-and-error approaches that dominate the field, a custom-built in-situ infrared spectroscopic experimental platform will be utilized during these studies to fundamentally interrogate the chemistry that governs bottom-up semiconductor nanowire synthesis and structure. The combination of an ultrahigh vacuum growth environment and in-situ measurement is transformative in its ability to limit nanowire degradation and access a level of chemical detail not previously achievable. It will be possible to clearly distinguish which surface species or combinations of surface species, as well as what specific bonding structures, most strongly influence nanowire structure. Si nanowires serve as a technologically relevant model system and will be the focus of this work, but key findings will be broadly applicable to a range of important semiconductor nanomaterials. The specific objectives are three fold: (1) determine the role of surface-bound hydrogen on nanowire crystal orientation, (2) control nanowire crystal structure through the organic functionalization of nanowire sidewalls during growth, and (3) modulate nanowire structure as a function of axial position to create novel superstructures. Results from these objectives will collectively serve as the basis for semiconductor nanowire chemistry-structure and structure-property relationships that are essential for realizing devices with advanced performance. Preliminary data has demonstrated the importance of surface chemistry during nanowire growth and provides a strong foundation from which to begin this research effort.Broader Impact: Breakthrough photovoltaic and thermoelectric technologies that could be widely deployed could transform our energy systems and reduce their carbon footprint. The insight gained during this work will greatly accelerate the design of nanoscale components for next generation devices, making a significant contribution to the United States declared goal of reducing carbon emissions over the coming years. Although this effort will be focused on energy conversion, advancements are expected to have broad applicability in a range of fields including photonics, electronics, quantum computation, and electrochemistry. In addition, students at all levels of STEM education, as well as the general public, will be prepared to intelligently discuss and navigate the emerging renewable energy landscape. The use of the Internet and social networking tools will directly integrate key outreach efforts into the daily activities of a broad, multidisciplinary audience. In particular, the Prof. Solar blog will be used to disseminate recent scientific and technological advances via short video vignettes produced in a format that leverages everyday experiences in an educational and entertaining manner. The PI is also involved in local outreach activities that focus on underrepresented minority students at the K-12 level. These efforts will be continued and broadened through speaking engagements and hands-on scientific demonstrations. In addition, Georgia Tech undergraduate students will have opportunities to participate in research internships.