Comprehensive model toward optimization of SAG In-rich InGaN nanorods by hydride vapor phase epitaxy

Area of Science:

• Materials Science
• Nanotechnology
• Semiconductor Physics

Background:

• Controlled growth of indium-rich indium gallium nitride (InGaN) nanorods (NRs) presents significant challenges.
• Indium gallium nitride nanostructures are crucial for optoelectronic devices.

Purpose of the Study:

• To demonstrate the fabrication of InGaN NRs with high indium content using selective area growth.
• To investigate and suppress the formation of parasitic nanowires on InGaN NRs.
• To understand the underlying mechanisms of nanowire formation during InGaN growth.

Main Methods:

• Selective area growth of InGaN NRs via hydride vapor phase epitaxy (HVPE).
• Systematic variation of Indium/Gallium (In/Ga) flow ratios to control indium content.
• Investigation of ammonia (NH3) partial pressure effects on nanostructure morphology.
• Development of a theoretical model to explain nanowire formation based on alloy decomposition.

Main Results:

• Successfully grew InGaN NRs with indium content up to 90% by adjusting the In/Ga flow ratio.
• Observed nanowire formation on NR surfaces, with density proportional to Ga content.
• Demonstrated significant reduction in nanowire density by increasing NH3 partial pressure.
• Theoretical model confirmed that nanowire formation is linked to InGaN alloy decomposition below a critical NH3 partial pressure.

Conclusions:

• Controlled growth of high-indium InGaN NRs is achievable via HVPE.
• Ammonia partial pressure is a critical parameter for suppressing nanowire formation.
• Understanding alloy decomposition mechanisms aids in controlling InGaN nanostructure morphology for device applications.