1.3um VCSELs using InGaAs/GaPAsSb Type-II Quantum Wells Grown on GaAs

1.3 mm垂直腔面发射激光器（VCSEL）是未来光纤10gb以太网和局域网的使能器件。在本提案中，我们提出了一种在GaAs衬底上单步外延生长的1.3 mm vcsel的新方法。基本思想是使用InxGa1-xAs/GaPyAszSb1-y-z/InxGa1-xAs ii型量子阱（QW）结构作为有源区。我们对所提出的ii型量子阱结构的初步理论和实验研究表明，这一想法是可行的。用一个详细的理论模型计算了ii型量子阱结构的跃迁能、电子和空穴波函数的重叠以及增益谱。结果表明，电注入量为10.1018 cm-3时，增益可达8000 cm-1。在理论设计的基础上，利用一种特殊配置的分子束外延（MBE）机生长了若干光致发光和LED结构的测试样品。透射电镜图像清晰地显示出定义良好的量子阱结构。从QW样品的强室温光致发光和从led的电致发光已经清楚地观察到。在本项目中，我们将重点关注三个主要任务：1)进一步详细的理论建模，并优化不同变化的InGaAs/GaPAsSb ii型量子阱的器件结构；2)新QW结构的MBE生长和材料表征，了解各种生长相关问题，并找到VCSELs的最佳生长条件；3)利用低温连续波和时间分辨光致发光光谱技术对InGaAs/GaPAsSb ii型量子阱的载流子寿命和光学性质进行了详细的物理研究；4)连续波vcsel的设备演示。拟资助博士生2名。也会有一些本科生通过他们的高级设计项目参与到这个项目中来。

1.3-mm vertical-cavity surface-emitting laser (VCSEL) is an enabling device for future optical 10Gbit Ethernet and local area network. In the present proposal, we propose a novel approach to make 1.3 mm VCSELs on GaAs substrates with a single step epitaxial growth. The basic idea is to use an InxGa1-xAs/GaPyAszSb1-y-z/InxGa1-xAs type-II quantum well (QW) structure as the active region. Our preliminary theoretical and experimental studies of the proposed type-II QW structure have shown that the idea is feasible. A detailed theoretical model has been used to calculate the transition energies, overlaps between electron and hole wavefunctions, and gain spectra for the type-II QW structures. The results show that a gain of 8000 cm-1 can be reached under an electric injection of 10.1018 cm-3. Based on the theoretical design, several test samples for photoluminescence and LED structures have been grown by a specially configured molecular beam epitaxy (MBE) machine. TEM images clearly show well-defined QW structures. Strong room temperature photoluminescence from the QW samples and electroluminescence from the LEDs have been clearly observed. In the present proposed program, we will focus on three major tasks: 1) Further detailed theoretical modeling of gain spectra and optimized device structures of different variation of the proposed InGaAs/GaPAsSb type-II QWs; 2) MBE growth and materials characterization of the new QW structures to understand various growth related issues and find the optimized growth conditions for the VCSELs; 3) Detailed physics study of the carrier life time and optical properties of the InGaAs/GaPAsSb type-II QWs using low temperature cw and time resolved photoluminescence spectroscopy; 4) Device demonstration of cw VCSELs.In the proposed program, 2 PhD students will be supported. There will be also several undergraduate students to be involved in part of the program through their senior design projects.