Muonium in Wurtzite Structured Semiconductors

纤锌矿结构半导体中的锷

• 批准号: 0102862
• 负责人: Roger Lichti
• 金额: $ 22.76万
• 依托单位: Texas Tech University
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2001
• 资助国家: 美国
• 起止时间: 2001-09-01 至 2005-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0102862&HistoricalAwards=false
• 关键词: Muonium; Wurtzite; Structured; Semiconductors

The defect states formed by muonium (Mu) in wurtzite structured semiconductors are investigated using a series of related techniques known as muon-spin rotation, resonance, and relaxation, or mSR. Muonium is effectively a very light isotope of hydrogen in which a positive muon replaces the proton. Results of these studies provide crucial information on the behavior of isolated hydrogen impurities in these materials. The focus will be on the group-III nitrides and the II-VI compounds; in particular, the wide gap materials currently being developed for short wavelength lasers and other electro-optical applications. Hydrogen is an important impurity in these materials that reacts with other impurities to modify the related electrical and optical properties, thus understanding its effects is crucial to engineering these materials for specific uses. The muonium studies will yield information on the isolated hydrogen precursor to so-called passivation complexes that is very difficult to obtain by any other means. The various sites and charge states for H (Mu) will be obtained, the motion or diffusive characteristics of each state will be examined, and various transitions between these states characterized. This project follows very successful studies of Mu in the cubic semiconductors in which a complete model of the dynamics of Mu states and transitions was developed. The hexagonal wurtzite structure has twice as many sites for Mu as diamond or zincblende structures making assignments of the observed sites and transitions more difficult. Mu forms a shallow donor in some of the II-VI compounds in addition to the usual deep-level states; thus the crossover from deep to shallow behavior will be investigated in II-VI alloys. The ultimate goal of this project is to provide sufficiently detailed characterization of the observed Mu states that an accurate dynamic model of muonium in the wurtzite materials can be realized. Experience with other semiconductors indicates that the Mu results yield a semi-quantitative model for H impurities. This research will be conducted with students who will receive training in preparation for useful employment in the scientific/technical workforce of the 21st Century. Understanding the role of hydrogen impurities in the semiconductors being developed for blue and UV lasers and other optical applications is crucial to engineering these materials for specific uses. However, many aspects of the behavior of hydrogen impurities have been extremely difficult to study directly. In this project, we investigate an artificially produced impurity known as muonium that is formed by implanting a short lived particle into these materials. Muonium mimics the behavior of hydrogen in essentially all its important properties, but is far easier to study. The materials we plan to investigate include gallium nitride, aluminum nitride and other semiconductor compounds. These laser materials have a common structure known as wurtzite and our main goal is to develop a complete model of the behavior of muonium (hydrogen) impurities in materials with this structure. Our previous very successful studies of muonium in more common semiconductors, such as silicon and gallium arsenide which have a cubic structure, provided a detailed picture of the properties of isolated hydrogen impurities in the cubic semiconductors and serves as a guide for the current work. The results of this project will provide the experimental data for comparison to the theoretical calculations currently being used to predict the behavior of hydrogen within the technologically important wurtzite semiconductors. Successful completion of this work will allow a better model of the long term effects of hydrogen on the electrical and optical properties of short wavelength laser materials, and how these effects may be modified by various processing steps and aging under typical device use conditions. This research will be conducted with students. They will receive training in a forefront area of contemporary condensed matter physics and materials science in preparation to enter the scientific/technical workforce of the 21st Century.

研究了纤锌矿结构半导体中由Mu形成的缺陷态，采用了一系列相关的技术，称为Muon-自旋旋转、共振和驰豫。Muonium实际上是氢的一种非常轻的同位素，其中正的Muon取代了质子。这些研究的结果为这些材料中孤立的氢杂质的行为提供了至关重要的信息。重点将放在第三类氮化物和第二类-第六类化合物上；特别是目前正在开发的用于短波长激光和其他电光应用的宽禁带材料。氢是这些材料中的一种重要杂质，它可以与其他杂质反应来改变相关的电学和光学性质，因此了解它的影响对于设计这些特定用途的材料至关重要。钚研究将提供有关所谓钝化复合体的孤立氢前体的信息，这是通过任何其他手段都很难获得的。将获得H(Mu)的各种格位和电荷态，考察每个态的运动或扩散特性，并表征这些态之间的各种跃迁。这个项目是在立方半导体中对Mu进行了非常成功的研究之后进行的，在这些研究中，建立了一个完整的Mu态和跃迁动力学模型。六方纤锌矿结构中Mu的位置是钻石或闪锌矿结构的两倍，这使得指定观察到的位置和转变变得更加困难。除了通常的深能级外，Mu还在一些II-VI化合物中形成浅施主；因此，我们将研究II-VI合金从深到浅的交叉行为。该项目的最终目标是提供对观察到的Mu状态的足够详细的表征，从而能够实现纤锌矿材料中Mu的准确动力学模型。对其他半导体的经验表明，Mu的结果为H杂质提供了一个半定量的模型。这项研究将与将接受培训的学生进行，为在21世纪的科学/技术劳动力中有用的就业做准备。了解氢杂质在为蓝光和紫外光激光器以及其他光学应用而开发的半导体中的作用，对于为特定用途设计这些材料至关重要。然而，氢杂质行为的许多方面都极难直接研究。在这个项目中，我们研究了一种人工产生的杂质，称为Muonium，它是通过向这些材料中注入短寿命粒子而形成的。Muonium基本上在所有重要性质上都模仿了氢的行为，但更容易研究。我们计划研究的材料包括氮化镓、氮化铝和其他半导体化合物。这些激光材料有一种被称为纤锌矿的共同结构，我们的主要目标是开发一个完整的模型，研究具有这种结构的材料中的钼(氢)杂质的行为。我们以前非常成功地对更常见的半导体中的Mu进行了研究，例如具有立方结构的硅和砷化镓，提供了立方半导体中孤立的氢杂质的详细性质的图景，并作为当前工作的指导。该项目的结果将提供实验数据，以便与目前用于预测具有重要技术意义的纤锌矿半导体中氢的行为的理论计算进行比较。这项工作的成功完成将使我们能够更好地模拟氢对短波长激光材料的电学和光学性能的长期影响，以及在典型的设备使用条件下，这些影响如何通过各种加工步骤和老化来修改。这项研究将在学生中进行。他们将接受当代凝聚态物理和材料科学前沿领域的培训，为进入21世纪的科学/技术劳动力做准备。