Shell Phase and Morphology Control for Emission Tuning in III-V Core/Shell Quantum Dots.

Area of Science:

• Materials Science
• Nanotechnology
• Semiconductor Physics

Background:

• Epitaxial shells on III-V semiconductor quantum dots (QDs) enhance fluorescence quantum efficiency and stability.
• Implementation in light emission technologies requires precise control over QD properties.

Purpose of the Study:

• To control shell morphology and crystal structure in heterovalent III-V/II-VI core/shell QDs.
• To investigate the effects of these controlled changes on QD emission properties.

Main Methods:

• Tuning ZnSe shell growth modes (kinetic to thermodynamic) by adjusting precursor reactivity.
• Employing high-temperature Ostwald ripening for controlled morphology.
• Utilizing quantum mechanical simulations to analyze band alignment and exciton confinement.

Main Results:

• Achieved controlled tuning of shell morphology (tetrahedral to spherical-like) and crystal structure (zinc-blende to wurtzite).
• Spherical QD architectures exhibited higher photoluminescence quantum yield (PLQY) and improved stability.
• Observed variations in core position within QDs under different growth modes.

Conclusions:

• Morphological and crystal-type differences significantly impact band alignment and exciton confinement.
• Tunable emission spectra and exciton dynamics were confirmed.
• This research advances understanding of heteroepitaxial growth for optimized QD design in light emission applications.