Electrons in Diamond

非技术描述金刚石通常被认为是新一代电力电子产品的理想半导体材料。一个关键的应用将是电网的现代化，以整合能源、能量存储和不同用户的需求，如直流和交流电力系统。此外，从钻石发射到水中的电子可以在各种应用中进行化学反应。这项研究将使用新的方法来修饰钻石及其表面，以实现这些应用。这一成果将支持钻石功率晶体管、用于通信的高频元件和向水中发射电子的开发，以实现与其他材料不可能发生的局部化学反应。该项目将与亚利桑那州立大学太阳表项目合作，该项目支持物理科学中的保留和多样性。与Sunial的活动包括与研究相关的研讨会、指导和发展一个面向社区成员和当地高中学生和教师的外展级别的科学会议。这些活动的目标是通过改善这些学生的保留和教育丰富机会，增加传统上代表不足的学生获得科学职业的机会。技术说明钻石是一种宽禁带半导体，具有出色的半导体性能，长期以来一直被认为有利于大功率和高频应用。由于具有特定的表面终止，钻石具有负的电子亲和力，可以将电子注入水中进行局部催化。与所有其他宽禁带半导体相比，钻石的高电子迁移率和空穴迁移率是不寻常的。虽然含硼的p型掺杂已经被很好地表征了20年，但含磷的n型掺杂最近在一些实验室取得了进展，了解钻石中的电子可以使基于电子传输和电子发射的新一代金刚石器件能够从导电带态进入真空或水中。这项提议的重点是电子注入和金刚石-电介质界面，以实现电子传输、限制和表面发射。这一提议将解决在钻石中实现电子的三个基本挑战：1)电子能否传输到钻石的导带中？金刚石的低电子亲和力或负电子亲和势意味着接触金属在金刚石表面的n型肖特基势垒较大，不利于电子注入。2)能否形成限制电子在钻石中的介电-钻石界面？限制电子的介电-半导体界面需要导带偏移量，其中介电导带的最小值高于金刚石导带的最小值。3)钻石表面的端接能使电子持续有效地发射到真空或水中吗？虽然氢终止的钻石具有负的电子亲和力，但其表面在真空或氧化环境中(包括水)是不稳定的。从该计划中获得的理解将为钻石作为电子或局部催化剂的半导体的新应用奠定基础。该奖项反映了NSF的法定使命，并已通过使用基金会的智力优势和更广泛的影响审查标准进行评估，被认为值得支持。

Nontechnical DescriptionDiamond is often considered as the ideal semiconductor material for a new generation of power electronics. A key application would be modernization of the electricity grid to integrate energy sources, energy storage and diverse users’ needs such as DC and AC power systems. Moreover, electrons emitted from diamond into water can enable chemical reactions for a variety of applications. The research will use new methods to modify diamond and its surface to enable these applications. The results will support the development of diamond power transistors, high frequency components for communications and electron emission into water for localized chemical reactions not possible with other materials. This project will collaborate with ASU Sundial, a program which supports retention and diversity in the physical sciences. The activities with Sundial include research related workshops, mentoring and the development of an outreach-level scientific conference, geared at community members and local high school students and teachers. The goal of these activities is to increase access to science careers to students who are traditionally under-represented, by improving retention and educational enrichment opportunities for these students.Technical Description Diamond is a wide band gap semiconductor with outstanding semiconductor properties that have long been recognized as beneficial for high power and high frequency applications. With specific surface termination, diamond has a negative electron affinity that can enable injection of electrons into water for localized catalysis. The high electron and hole mobilities of diamond are unusual compared to all other wide band gap semiconductors. While p-type doping with boron has been well characterized for two decades, n-type doping with phosphorus has recently advanced in a number of laboratories, and understanding Electrons in Diamond could enable a new generation of diamond devices based on electron transport and electron emission from conduction band states into vacuum or water. The focus of this proposal is on electron injection and diamond-dielectric interfaces to enable electron transport, confinement, and surface emission. This proposal will address three fundamental challenges to achieving Electrons in Diamond: 1) Can electrons be transported into the conduction band of diamond? The low or negative electron affinity of diamond means that the n-type Schottky barrier for contact metals on diamond will be large and prohibit electron injection. 2) Can a dielectric-diamond interface be formed that confines electrons in diamond? A dielectric-semiconductor interface to confine electrons requires a conduction band offset where the dielectric conduction band minimum is above the diamond conduction band minimum. 3) Can a surface termination of diamond enable continued efficient electron emission into vacuum or water? While hydrogen terminated diamond has a negative electron affinity, the surface is unstable in vacuum or oxidizing environments including water. The understanding gained from this program will set the stage for new applications of diamond as a semiconductor for electronics or localized catalysis.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.