Spectroscopy of the electronic structure of coupled quantum dots systems

The decreasing feature size needed for new electronic devices has led to an interest in nanostructures such as quantum dots (QDs). Research on single QDs has successfully determined the electrical and optical properties of single layers of QDs. The search for novel devices such as QD memory or development of a quantum bit (Qbit) for quantum computing have led to an increased interest in coupled systems of QDs.; Research aimed at investigating the electronic structure of coupled QD systems is presented in this thesis. The optical properties of strain-induced QDs (SIQDs) are investigated using photoluminescence (PL) spectroscopy. SIQDs were formed by strain coupling between a GaAs QW and an InAs QD layer. A model, first introduced by J. Davies, was further developed through collaboration with Claus Metzner to try and fit the experimental data.; The strain coupled pairs of SIQDs and QDs were inserted into a quantum dot memory (QDM) device. Spectroscopy on the device was successful at showing both charge separation and exciton storage in the structure. Time-resolved PL (TRPL) measurements demonstrated a storage time of 3 seconds.; Single pairs of quantum and strain coupled InAs QDs were investigated by mu-PL using a new NIN structure. Such measurements identified quantum coupling effects between the two layers when separated by 45A. This coupling was also found to be adjustable by varying the electric field across the structure, making it a potentially attractive candidate for quantum computing as a Qbit. A model developed by Claus Metzner was used to model the observed coupling behavior.