Study of Doping in ZnBe Chalcogenide Alloys via MBE Growth with use of Non-Equilibrium Concepts

该项目旨在更好地理解宽禁带半导体中的双极掺杂。该项目的主要目的是研究MBE生长过程中非平衡对掺杂的影响，并利用所获得的见解来改进掺杂。ZnSe和相关合金（主要是氮掺杂）将被用作测试系统。该项目的另一个目标是应用由此产生的理解来改善ZnBe和可能的ZnCdBe硫系合金的掺杂，因为这些合金是潜在的改进znse基蓝绿色二极管激光器器件寿命的候选材料。计划研究的MBE生长的具体方面是平面掺杂，金属/硫族化物比的变化，和/或晶体取向的变化。进一步的目标是研究和可能消除DX中心使用平面掺杂技术。平面掺杂将与掺杂剂和不同的硫族化合物（如znmgse的Te）一起使用，以改变这些中心的局部环境，从而从现有的一些体系中消除它们——据报道，同时使用Te/N平面掺杂不仅使ZnSe中的空穴浓度几乎提高了一个数量级，而且还改变了电离能，接近ZnTe的值。消除DX中心将是一项重大的技术和基础突破。除了生长研究外，还计划协调生长与补偿物种的确定。考虑到掺杂的非平衡性，不同的补偿种在不同的条件下可能占主导地位。将主要通过发光、正电子湮灭光谱和光学探测磁共振等方法，研究各种生长方法产生的补偿物质。该项目涉及具有高技术相关性的材料科学主题领域的基础研究问题。该研究将在基础层面上为电子/光子器件的重要方面贡献基础材料科学知识。现在有了实验工具，可以在原子水平上观察材料缺陷及其起源，更好地理解这些缺陷将促进基础科学和技术的进步。从研究中获得的基本知识和理解有望通过为设计和生产改进的材料和材料组合提供基本的理解和基础，从而有助于提高先进设备的性能和稳定性。该计划的一个重要特点是通过培养学生在一个基础和技术上重要的领域的研究和教育的整合。

9805760 Neumark This project aims for greater understanding of bipolar doping in wide bandgap semiconductors. A primary aim of the project to investigate nonequilibrium effects on doping during MBE growth, and to use the insight gained to improve doping. ZnSe and related alloys (with mainly nitrogen doping) will be used as a test system. A further aim of the project is to apply the resultant understanding to improve doping in ZnBe, and possibly ZnCdBe chalcogenide alloys, since these alloys are candidates for potential improvements in device lifetimes of ZnSe-based blue-green diode lasers. Specific aspects of MBE growth planned for investigation are planar doping, changes in the metal/chalcogenide ratio, and/or changes in crystallographic orientation. A further objective is to study and possibly eliminate DX centers by use of the planar doping technique. Planar doping will be used with both the dopant and a different chalcogenide (such as Te for ZnMgSeS) to modify the local environment of such centers so as to eliminate them from some systems where they now exist--it has been reported that simultaneous Te/N planar doping gives not only almost an order of magnitude improvement in hole concentrations in ZnSe, but also changes the ionization energy to close to the ZnTe value. Elimination of DX centers would be a major technological and fundamental breakthrough. In addition to the study of growth, it is also planned to coordinate growth with determination of compensating species. Considering non-equilibrium aspects of doping, different compensating species may dominate under different conditions. Compensating species resulting from various growth approaches will be studied, primarily via luminescence, positron annihilation spectroscopy, and optically detected magnetic resonance. %%% The project addresses basic research issues in a topical area of materials science having high technological relevance. The research will contribute basic materials science knowledge at a fundamental level to important aspects of electronic/photonic devices. Experimental tools are now available to allow atomic level observation of materials defects and their origins which when better understood will allow advances in both fundamental science and technology. The basic knowledge and understanding gained from the research is expected to contribute to improving the performance and stability of advanced devices by providing a fundamental understanding and a basis for designing and producing improved materials, and materials combinations. An important feature of the program is the integration of research and education through the training of students in a fundamentally and technologically significant area.