Epitaxial Growth of Semiconductor Quantum Dots: An Overview

Quantum dots (QDs) play an important role in fabricating electronic, photonic, and optoelectronic devices with enhanced functions and performance. There are two typical epitaxial methods for growing semiconductor QDs, one is stress-driven self-assembly, i.e., Stranski-Krastanov (S-K), and the other is droplet epitaxy (DE). The former was developed faster in earlier years and usually referred to as conventional method while the latter has attracted increasing interest in recent years driven by increasing requirement for high quality QDs towards quantum computing applications. Physically, the nucleation of QDs in both methods are self-assembly surface reactions, which have limited site-control for nucleation on flattened substrate. Pre-patterning of substrate was developed to regularly locate the nucleation sites but may also cause undesired contaminations. Laser-interference-assisted growth has emerged in the past few years, which provides a non-contact in-situ patterning for the nucleation of QDs arrays. This overview provides a glimpse of recent advances in epitaxial growth of QDs towards their advanced photonic and optoelectronic applications.