Collaborative Research: Studies of Electron Injection-Induced Effects in ZnO-based Materials and Device Structures

合作研究：ZnO基材料和器件结构中电子注入诱导效应的研究

• 批准号: 0900978
• 负责人: Jianlin Liu
• 金额: $ 24.49万
• 依托单位: University of California-Riverside
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2009
• 资助国家: 美国
• 起止时间: 2009-08-01 至 2013-07-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0900978&HistoricalAwards=false
• 关键词: Collaborative; Research; Studies; Electron; Injection

ECCS 0900971/0900978Collaborative Research: Studies of Electron Injection-Induced Effects in ZnO-based Materials and Device Structures With recent advances in ZnO epitaxial growth and processing, it is very likely that efficient minority carrier devices, such as light emitting diodes, laser diodes and transparent p-n junctions, can be achieved in the near future. Because the minority carrier diffusion length - one of the critical parameters in defining p-n junction performance - is usually less than 1 micron in ZnO-based semiconductors, it is imperative to find ways of its improvement. The principal investigators¡¦ recent findings indicate that the minority carrier diffusion length can be elongated in p-type ZnO due to electron injection. While the observed novel effect was attributed to electron trapping on impurity-related levels, the role of extended and point defects as well as of surface states was not completely excluded. The intellectual merit of this research is in exploration of electron injection¡¦s impact on minority carrier transport and recombination in ZnO and related compounds. A wide range of epitaxial antimony-doped p-type ZnO and p-type Zn1-xMgxO (x ?T 0.15) layers will be studied. In addition, the minority carrier transport in p-ZnO doped with other impurities such as phosphorus, or nitrogen, as well as in p-type Zn1-xCdxO (x ?T 0.15) and Zn(Mg/Cd)O/ZnO superlattices, will be investigated. Magnesium (Cadmium) incorporation into the ZnO lattice and barrier and well presence in the superlattices create electron injection conditions different from that in ZnO. To fully understand the effects of electron injection in Zn(Mg/Cd)O and to find conditions under which they can be employed, systematic electrical and optical studies will be carried out in the representative range of device structures: p-n junction and Schottky diodes. Electrical testing, combined with Electron Beam-Induced Current measurements, will be performed in-situ in a Scanning Electron Microscope. These measurements will be complemented with in-situ cathodoluminescence as well as spectral photoresponse and transient photocurrent measurements.The effects of electron injection to be investigated are likely related to concentration of dopants, epitaxial layer quality and composition. Therefore, the study of materials with variations in these properties is necessary. The growth of these materials and the fabrication and characterization of their device structures are assured through the interactive collaboration between the groups at the University of Central Florida and the University of California, Riverside. The practical significance of the proposed research is in performance control of p-n junction charge collection semiconductor devices, such as photodetectors, in which the minority carrier diffusion length plays a critical role. A several-fold increase in the photodetector¡¦s quantum efficiency is anticipated relative to the current state-of-the-art of ~ 15-20%. The broader impact of this collaborative project is in better understanding the fundamentals of point and extended defects in ZnO-based semiconductors, creating a partnership between two universities, and integrating research and education at the graduate, undergraduate and K-12 levels, as expressed in participation of underrepresented Ph.D. students, several undergraduates and local high school students in the proposed research. These students will build skills in collaborating on a long-term, long-distance academic project, as they participate in the proposed research.

ECCS 0900971/0900978合作研究：ZnO基材料和器件结构中的电子注入诱导效应研究随着ZnO外延生长和加工的最新进展，在不久的将来，很可能实现高效的少数载流子器件，如发光二极管，激光二极管和透明p-n结。 由于ZnO基半导体中的少数载流子扩散长度（定义p-n结性能的关键参数之一）通常小于1微米，因此必须找到改善其性能的方法。主要研究人员……最近的研究结果表明，由于电子注入，p型ZnO中的少子扩散长度可以被延长。虽然所观察到的新的效果是由于电子捕获杂质相关的水平，扩展和点缺陷以及表面状态的作用并没有完全排除。 本研究的学术价值在于探索电子注入对ZnO及相关化合物中少子输运和复合的影响。外延锑掺杂的p型ZnO和p型Zn 1-xMgxO（x？T0.15）层进行了研究。此外，还研究了掺杂其它杂质（如磷、氮）的p-ZnO和p-型ZnO中的少子输运特性。 Zn_（1-x）Cd_xO（x？T0.15）和Zn（Mg/Cd）O/ZnO超晶格。镁（镉）掺入到ZnO晶格和势垒和良好的存在下，在超晶格中创建电子注入条件不同于在ZnO。为了充分理解Zn（Mg/Cd）O中电子注入的影响并找到它们可以使用的条件，将在具有代表性的器件结构范围内进行系统的电学和光学研究：p-n结和肖特基二极管。将在扫描电子显微镜中原位进行电气测试和电子束感应电流测量。这些测量将补充原位阴极发光以及光谱光响应和瞬态光电流测量。电子注入的影响进行调查可能涉及掺杂剂的浓度，外延层的质量和成分。因此，研究这些性质变化的材料是必要的。这些材料的生长及其器件结构的制造和表征通过中央佛罗里达大学和加州大学滨江分校的小组之间的互动合作得到保证。 该研究对p-n结电荷收集半导体器件（如光电探测器）的性能控制具有实际意义，其中少数载流子扩散长度起着关键作用。预计光电探测器的量子效率将比目前的15- 20%提高数倍。这个合作项目的更广泛的影响是更好地了解ZnO基半导体的点缺陷和扩展缺陷的基本原理，在两所大学之间建立合作伙伴关系，并整合研究生，本科生和K-12水平的研究和教育，如代表性不足的博士参与所示。学生，几个本科生和当地高中生在拟议的研究。这些学生将建立在一个长期的，远距离的学术项目合作的技能，因为他们在拟议的研究参与。