Yu-Chen Chang

PhD student

Research Overview

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

  • Quantum Nanotechnology