From Atoms to Nanomaterials: Controlling Atomic Behavior to Create Useful Nanostructures

We use molecular beam epitaxy (MBE) to grow quantum dot (QD) nanomaterials for future optoelectronic applications such as solar cells and quantum computers. Understanding how different materials and MBE growth parameters affect QD properties is key to successfully integrating these objects into devices. In our study, we use atomic force microscopy to determine the height, diameter, areal density, and interdot spacing of Ge and GaAs QDs. We use this data to calculate island scaling curves for analysis of QD size distributions, and radial distribution scaling curves to find the probability of encountering a QD at some radius from another dot. This information tells us about QD growth kinetics and thermodynamics, which is crucial for optimizing QD properties for future devices. For example, our island scaling results reveal narrower QD size distributions for Ge QDs compared to GaAs QDs, indicating higher areal density and Ge diffusion length during MBE growth