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

点击翻译按钮获取中文摘要

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.