GOALI: Defect Formation and Phase Transitions in 2-5 Micron GaInAsSb Semiconductor Quaternary Alloys versus Ga(In)Sb/InAs Short Period Superlattices

技术：该项目研究Sb III-V材料的相变和缺陷形成，包括直接带隙四元材料GaInAsSb和具有2-5微米光谱范围的带隙的InAs/Ga(In)Sb超晶格。这些材料有望在红外光电子器件中发挥越来越重要的作用，包括光电二极管探测器、发光二极管、激光二极管和热光电。然而，根据热力学计算，在热力学平衡条件下生长在GaSb衬底上的GaInAsSb合金在合金相空间中存在不混溶区域，潜在地限制了所需成分的稳定性。这个项目将研究和绘制出应变和生长动力学对热力学不混溶区域的量子阱GaInAsSb合金的影响。成像技术将用于研究特征缺陷的形成、相分离和调幅分解。光致发光、吸收和光学寿命测量将被用来关联形态和光学性质，包括辐射和非辐射衰减过程。具有覆盖2-5微米波长范围的直接带隙的短周期II型InAs/Ga(In)Sb超晶格(T2SL)的替代材料也将被讨论。它们与GaInAsSb合金有几个共同的特征，包括共同的元素组成，以及由于混合而在界面和层中的GaInAsSb区域。该项目旨在促进对GaInAsSb合金和InAs/Ga(In)Sb超晶格晶体生长和材料特性的最先进了解，并允许在美国大学的研究级MBE反应堆和IQE的工业级MBE反应堆进行测试。通过ASL Analytical提供的理论计算，将获得这些材料的测量和计算性能之间的比较的新的、全面的数据。非技术性：这个GOALI(与工业联系的机会)项目解决了材料科学的一个具有高度技术相关性的主题领域的基础研究问题。爱荷华大学学术小组和行业合作伙伴、IQE和ASL Analytical之间的协作联系是协同的，并为科学、技术和教育影响提供了有利的机会。PI将招募和雇用一名新的毕业生和本科生参与该项目，并在研究生完成博士学位后为其提供建议。研究生将获得在学术(UIA)和工业(IQE，ASL)环境中工作的研究经验。国际和平研究所将重振加州大学洛杉矶分校的物理和天文学扩展项目，名为“科学中的家庭冒险”，由不同的教职员工向公众发表一系列关于同一主题的讲座；其中一个主题将是半导体。此外，国际和平研究所将为一年级学生举办一次一个学分的研讨会，通过几位著名科学家的研究来了解科学的方法。

Technical: This project addresses phase transitions and defect formation in antimonide III-V materials, including direct gap quaternary materials GaInAsSb and InAs/Ga(In)Sb superlattices having bandgaps covering the 2-5 micron spectral range. These materials are expected to be of growing importance to infrared optoelectronic devices, including photodiode detectors, light emitting diodes, laser diodes, and thermophotovoltaics. However, GaInAsSb alloys grown under thermodynamic equilibrium conditions unstrained on GaSb substrates have immiscibility regions in the alloy phase space according to thermodynamic calculations, potentially limiting stability of desired compositions. This project will study and map out the influence of strain and growth kinetics on quantum well GaInAsSb alloys across the thermodynamic immiscibility region. Imaging techniques will be used to study characteristic defect formation, phase separation, and spinodal decomposition. Photoluminescence, absorption and optical lifetime measurements will be used to correlate morphology and optical properties, including radiative and nonradiative decay processes. Alternative materials to GaInAsSb alloys with direct gaps covering the 2-5 micron wavelength region, short-period, type-II InAs/Ga(In)Sb superlattices (T2SL) will be addressed as well. They have several characteristics in common with GaInAsSb alloys, including common elemental composition, as well as GaInAsSb regions at interfaces and in layers due to intermixing. The project aims to advance state-of-the-art understanding of crystal growth and material properties of GaInAsSb alloys and InAs/Ga(In)Sb superlattices, and allows testing at both research grade MBE reactors at U. IA as well as industrial grade MBE reactors at IQE. New, comprehensive data will be obtained on comparisons between measured and calculated properties of these materials, with theoretical calculations provided by ASL Analytical. Non-technical: This GOALI (Grant Opportunities for Liaison with Industry) project addresses basic research issues in a topical area of materials science with high technological relevance. Collaborative links between the University of Iowa academic group and industrial partners, IQE and ASL Analytical are synergistic, and provide advantageous opportunities for scientific, technological, and educational impacts. The PI will recruit and hire a new graduate and undergraduate student to work on the project and advise the graduate student through the completion of his or her PhD. The graduate student will get research experience working both in academic (U. IA) and industrial (IQE, ASL) environments. The PI will reinvigorate a U. IA Physics and Astronomy outreach program called "Family Adventures in Science," featuring a series of lectures on a theme by different faculty members to the public; one of the themes will be semiconductors. Additionally, the PI will propose a one credit seminar for first year students on approaches to science through study of several famous scientists.