Engineering Silicon/Silicon-Germanium Nanostructure Heterointerfaces: Toward Group IV Light Emitters and Lasers

该项目开发和制备了Ge浓度接近50%的Si(Si)/Si-Ge(Ge)纳米结构和陡峭的Si/SiGe异质界面。其目标是展示一种与cmos兼容的光发射器的原型，并可能展示一种在近红外下工作的激光器。最近的PI研究表明，在Ge含量大于20%、结构缺陷密度较低的Si/SiGe纳米结构中，发光过程完全由Si/SiGe异质界面控制。在这些纳米结构中，第二类能带排列和扩散的Si/SiGe异质界面(由于Si/SiGe混合)导致了电子和空穴的空间分离和缓慢的辐射复合。在中、高载流子浓度下，这种缓慢的复合不能与俄歇过程竞争，发光量子效率急剧下降。在这个项目中，他们将利用一种基于快速热低压化学气相沉积的制备技术，制备具有低缺陷密度和突变异质界面的富Ge Si/SiGe纳米结构。在这些纳米结构中，电子和空穴波函数的重叠将得到增强，辐射复合将加速许多数量级。研究计划集中在：(A)具有突变异质界面的富Ge Si/SiGe纳米层的制备和详细的结构表征；(B)在这些纳米结构中的应变工程以及应变在改变Si/SiGe异质界面上的能带排列方面的应用；(C)突变和应变的Si/SiGe异质界面上载流子复合的实验研究和模拟；以及(D)展示包括光泵浦光发射器和可能的激光器在内的光子器件原型。本研究项目致力于开发与CMOS兼容的高效率发光器件和激光器。如果成功，该项目将成为长期探索成功将光源集成到CMOS环境中的里程碑式的成就。该项目还包括在具有战略重要性的半导体纳米技术领域对NJIT的研究生和本科生进行全面培训；整合研究和教育；促进新泽西州的一所公立大学、加利福尼亚州帕洛阿尔托的惠普研究实验室和加拿大国家研究委员会之间的伙伴关系。这一研究项目的一个重要组成部分是纳米技术的公共教育，并通过讲座、演示、实验室参观和针对纽瓦克和新泽西大都市区的高中生和教师的暑期研究计划，向科学和技术领域中代表性不足的群体开展外联工作。

This project develops and fabricates Silicon (Si)/Si-Germanium(Ge) nanostructures with Ge concentration approaching 50% and abrupt Si/SiGe heterointerfaces. The goal is to demonstrate a prototype of a CMOS-compatible light emitter and, possibly, a laser operating in the near infrared. Recently, the PI showed that in Si/SiGe nanostructures with Ge concentration greater than 20% and low structural defect density, the process of light emission is fully controlled by Si/SiGe heterointerfaces. In these nanostructures, type II energy band alignment and diffused Si/SiGe heterointerfaces (due to Si/SiGe intermixing) are responsible for electron and hole spatial separation and slow radiative recombination. At moderate and high carrier concentration, this slow recombination cannot compete with Auger processes, and luminescence quantum efficiency decreases drastically. In this project, they will utilize a fabrication technique based on rapid thermal low-pressure chemical vapor deposition and fabricate Ge-rich Si/SiGe nanostructures with low defect density and abrupt heterointerfaces. In these nanostructures, electron and hole wavefunction overlap will be enhanced and radiative recombination will be accelerated by many orders of magnitude. The research plan is focused on (a) fabrication and detailed structural characterization of Ge-rich Si/SiGe nano-layers with abrupt heterointerfaces; (b) strain engineering in these nanostructures and application of strain for modification of energy band alignment at Si/SiGe heterointerfaces; (c) experimental studies and modeling of carrier recombination at abrupt and strained Si/SiGe heterointerfaces; and (d) demonstration of photonic device prototypes including optically and electrically pumped light emitters and, possibly, lasers. This research project is focused on the development of CMOS compatible, high efficiency light emitters and lasers. If successful, this project will become the milestone achievement in the longtime search for successful light source integration into the CMOS environment. The project also includes comprehensive training of NJIT graduate and undergraduate students in the strategically important areas of semiconductor nanotechnology; integration of research and education, and promotion of a partnership between a public university in New Jersey, Hewlett Packard Research Laboratories in Palo Alto, CA and National Research Council of Canada. An important component of this research project is public education in nanotechnology and outreach efforts to underrepresented groups in science and technology via lectures, demonstrations, laboratory tours and summer research programs for high-school students and teachers in Newark and New Jersey Metropolitan Area.