Ultrafast and magneto-optical spectroscopy of semiconductor heterostructures

Abstract

This thesis presents spectroscopic results using semiconductor heterostructures important for both applied and fundamental physics. First, we studied short-period superlattices of InAs and GaSb that suggest a promising alternative to mercury cadmium telluride for mid-infrared detection. Our time-domain measurements help sample growers optimize growth conditions to maximize the carrier lifetime and determine the superlattice period and interface quality. The second area of research has a more fundamental focus. Here, we study the time-integrated emission and time-resolved population and emission properties of high-density excitons in an InGaAs quantum well sample in strong perpendicular magnetic field. Our time-integrated results indicate that two-dimensional magneto-excitons can appear to be stable against a Mott transition with the application of magnetic field. Our time-resolved results provide the first direct observation of superfluorescence using a semiconductor showing the population inversion of magneto-excitons suddenly drop from fully excited to completely unexcited emitting an intense pulse of coherent radiation.