Self-catalyzed GaAsP nanowires grown on silicon substrates by solid-source molecular beam epitaxy

Area of Science:

• Materials Science
• Nanotechnology
• Semiconductor Physics

Background:

• Gallium Arsenide Phosphide (GaAsP) nanowires (NWs) are promising for silicon-integrated optoelectronics.
• Achieving high crystal quality and controlled morphology in GaAsP NWs on silicon remains a challenge.

Purpose of the Study:

• To demonstrate the growth of self-catalyzed GaAsP nanowires on silicon (111) substrates.
• To investigate the effects of phosphorus incorporation on nanowire nucleation, morphology, and crystal quality.
• To explore the potential of GaAsP core-shell nanowires for optoelectronic applications.

Main Methods:

• Solid-source molecular beam epitaxy (MBE) was employed for nanowire growth.
• Optimization of V/III and P/As flux ratios, and Ga flux.
• Comparison of growth kinetics between vapor-liquid-solid (VLS) and vapor-solid (VS) growth modes.

Main Results:

• High-crystal-quality GaAsP NWs with a near-pure zinc-blende phase were achieved.
• Phosphorus incorporation significantly influenced catalyst nucleation energy, affecting NW morphology and quality.
• Radial GaAsP shell growth on core GaAsP NWs demonstrated room-temperature emission at ~710 nm.

Conclusions:

• Phosphorus incorporation is crucial for controlling GaAsP nanowire properties.
• Understanding growth kinetics differentiates VLS and VS modes.
• Self-catalyzed GaAsP core-shell nanowires offer a pathway for silicon-based photovoltaics and visible light emitters.