Engineering Photonic Devices and Materials Through Quantum Confinement and Electromagnetic Design

摘要

In this effort, devices which used quantum confinement for light emission were designed. Two methods of quantum confinement were investigated; Si quantum dots (nanocrystals) and III-V pyramidal quantum dots. Investigation of Si nanocrystals included studies of the effects of varying silicon layer thickness and their agreement with quantum confinement theory. Along with photoluminescence, electroluminescence of silicon nanocrystals films was investigated under both DC and pulsed pumping. A power conversion efficiency of approximately 3-0-6 was obtained at low current densities for these nanocrystals structures. Microdisk and microgear cavities were made and quality factors were extracted from these devices. An alternative approach to MBE growth of AlGaAs quantum dots was taken in this work. The fabrication approach that was used was to grow complete layers with MBE processing and then selectively etch the structures. Pyramid type structures were created in these materials with a combination of wet and dry etch techniques. The effects of the concentration of Al on the AlGaAs on etch rates and selectivity were investigated as a key part of the project. The process was refined to be able to create high density quantum confinement structures.