Reflectance difference spectroscopy microscope for circular defects on InN films

Area of Science:

• Materials Science
• Surface Science
• Optical Microscopy

Background:

• Microstructural defects significantly impact material properties.
• Characterizing nanoscale surface features is crucial for material development.
• Optical anisotropy provides insights into material strain and topography.

Purpose of the Study:

• To introduce and validate a novel Reflectance Difference Spectroscopy microscope (μ-RDS).
• To demonstrate the capability of μ-RDS in characterizing microstructural defects on Indium Nitride (InN) films.
• To correlate μ-RDS data with surface topography and strain fields.

Main Methods:

• Utilizing a custom-built Reflectance Difference Spectroscopy microscope (μ-RDS).
• Acquiring reflectivity and reflectance difference (RD) images through sample rotation.
• Cross-validating μ-RDS results with Atomic Force Microscopy (AFM) and Raman mapping.
• Employing simulation techniques to analyze defect models.

Main Results:

• The reflectivity image from μ-RDS accurately maps defect topography, size, and location.
• Standard four-polar RD image distribution was observed for uniform height fluctuations.
• Non-standard RD distributions indicated the presence of strain fields and non-uniform height fluctuations.
• μ-RDS successfully identified optical anisotropy induced by height and strain variations.

Conclusions:

• Reflectance Difference Spectroscopy microscope (μ-RDS) is a reliable tool for microstructural defect characterization.
• μ-RDS provides detailed information on surface topography and subsurface strain fields.
• The technique is valuable for analyzing optical anisotropy in materials with nanoscale defects.