Optical Emission of Individual GaN Nanocolumns Analyzed with High Spatial Resolution

Area of Science:

• Materials Science
• Semiconductor Physics
• Nanotechnology

Background:

• Gallium Nitride (GaN) nanostructures are crucial for optoelectronic devices.
• Understanding defects like basal plane stacking faults (BSFs) is key to improving GaN material quality.
• High-resolution characterization techniques are needed to study nanoscale properties.

Purpose of the Study:

• To fabricate a homogeneous array of high-quality GaN nanocolumns (NCs) using selective area growth.
• To investigate the structural and optical properties of individual GaN NCs at the nanometer scale.
• To correlate nanoscale structural defects with optical emission properties.

Main Methods:

• Fabrication of GaN nanocolumns via selective area growth.
• Nanoscale structural analysis using transmission electron microscopy (TEM) and scanning transmission electron microscopy (STEM).
• Spatially resolved cathodoluminescence (CL) spectroscopy at liquid helium temperatures.

Main Results:

• Achieved a homogeneous array of GaN NCs with high crystal quality and remarkably low BSF density.
• TEM analysis confirmed excellent structural properties of the GaN NCs.
• Direct correlation between CL emission at 360.6 nm and the location of type I1 BSFs was observed.

Conclusions:

• Selective area growth is effective for producing high-quality GaN NCs with minimal defects.
• Individual BSFs in GaN NCs can be characterized due to low overall defect density.
• A distinct optical emission signature is associated with type I1 BSFs in GaN nanostructures.