Self-assembled nanodisks in coaxial GaAs/GaAsBi/GaAs core-multishell nanowires

Area of Science:

• Materials Science
• Nanotechnology
• Semiconductor Physics

Background:

• III-V semiconductor nanowires (NWs), particularly gallium arsenide (GaAs), are crucial for optoelectronics and nanophotonics.
• Incorporating bismuth (Bi) into GaAs (GaAsBi) offers tunable electronic and optical properties due to unique band structure and bandgap bowing.

Purpose of the Study:

• To investigate the effects of Bi alloying in GaAs NWs.
• To explore the formation and properties of self-assembled nanostructures induced by Bi segregation.
• To assess the potential for novel quantum structures in optoelectronic applications.

Main Methods:

• Growth of GaAsBi nanowires via alloying.
• Characterization of Bi-induced nanostructures using microscopy and spectroscopy.
• Analysis of optical properties, including emission polarization and linewidth.

Main Results:

• Bi alloying induces the formation of optically active, self-assembled nanodisks due to Bi segregation.
• These nanodisks are located at specific crystallographic corners (112) and restricted to twin planes.
• Higher Bi composition in nanodisks leads to strong exciton confinement and narrow emission lines (<450 μeV) with polarization orthogonal to the NW axis.

Conclusions:

• Bismuth segregation in GaAs NWs enables the creation of self-assembled quantum structures.
• These findings open avenues for advanced nanophotonic devices by combining dilute bismide alloys and nanowire lattice engineering.
• The unique optical properties of these nanodisks are promising for next-generation near-infrared optoelectronics.