Yu-Chen ChangPhD student
In the optoelectronics group at Lancaster University my research focuses on the use of novel Droplet epitaxy (DE) mode to fabricate semiconductor quantum dots (QDs) GaAs/AlGaAs by molecular beam epitaxy (MBE). Traditionally, QDs are grown using Stranski-Krastanow mode, however, this is restricted to lattice-mismatched materials, and typically yields QDs suffering from intermixing and strain related effect.
Droplet epitaxy (DE) is a promising growth method to fabricate high-density, strain-free QDs with no limitation on the stacking number or the spacer-layer thickness. By controlling the experimental parameters including flux, temperature, and substrate orientation, high areal density of QDs are formed. In my research, the structure and optical properties of high-density GaAs/AlGaAs quantum dots (QDs) fabricated by DE approach is investigated by using atomic force microscopy (AFM), scanning electron microscopy (SEM), beam exit polishing (BEXP), and photoluminescence