Structural dynamics of GaN microcrystals in Evolutionary Selection Selective Area Growth probed by X-ray...

Area of Science:

• Materials Science
• Crystallography
• Semiconductor Physics

Background:

• Achieving high-quality, single crystalline semiconductor material independent of the substrate is key for cost-effective optoelectronic device enhancement.
• The novel Evolutionary Selection Selective Area Growth (ES-SAG) process offers a potential solution for substrate-insensitive growth.

Purpose of the Study:

• To investigate the structural properties of Gallium Nitride (GaN) microcrystals grown using the ES-SAG method.
• To understand the influence of growth structure dimensions on the ES-SAG mechanism and the resulting GaN microcrystal properties.

Main Methods:

• Utilized X-ray microdiffraction for high-resolution structural analysis in both direct and reciprocal spaces.
• Examined GaN microcrystals grown within different dimensions of growth constrictions (tunnels).

Main Results:

• Identified that specific growth tunnel widths (2.6 μm and 4.5 μm) favor the evolutionary selection mechanism in ES-SAG.
• Observed that wider growth tunnels (8.6 μm) do not support this mechanism as effectively.
• Found that GaN microcrystal ensembles exhibit a slight tensile strain, regardless of the growth tunnel dimensions.

Conclusions:

• The geometric proportions of growth constrictions critically influence the effectiveness of the ES-SAG process.
• ES-SAG shows promise for producing high-quality GaN microcrystals with controlled structural properties.
• The inherent tensile strain in GaN microcrystals warrants further investigation for device applications.