Optical properties demonstrating strong coupling of compactly arranged Ge quantum dots

Area of Science:

• Materials Science
• Condensed Matter Physics
• Nanotechnology

Background:

• Coupled quantum dots (QDs) show unique collective properties.
• Potential applications in optoelectronic devices are being explored.

Purpose of the Study:

• To investigate the photoluminescence (PL) properties of dense, in-plane germanium quantum dots (QDs).
• To understand the effects of excitation power and temperature on QD ensemble PL.

Main Methods:

• Fabrication of dense germanium quantum dots with in-plane arrangement.
• Systematic power-dependent and temperature-dependent photoluminescence (PL) spectroscopy.

Main Results:

• Observed a PL peak with high intensity, constant energy, and width under varying excitation power.
• Demonstrated a red-shift and rapid PL quenching with increasing temperature.
• Attributed these properties to miniband formation and hole delocalization in the coupled QD ensemble.

Conclusions:

• Strong coupling between adjacent QDs leads to miniband formation.
• Hole delocalization significantly influences the observed PL characteristics.
• These findings are crucial for advancing QD-based optoelectronic devices.