photoluminescence mapping

**PL Mapping** is a **technique that records photoluminescence spectra or intensities at multiple positions across a wafer or sample** — creating spatial maps of band gap, emission intensity, peak wavelength, and linewidth that reveal material uniformity and defect distributions. **How Does PL Mapping Work?** - **Scanning**: Move the laser spot across the sample on a grid (or move the sample under a fixed laser). - **Per-Point**: Record the full PL spectrum (or intensity at a specific wavelength) at each position. - **Maps**: Generate contour maps of peak intensity, peak position (wavelength/energy), and FWHM. - **Resolution**: Typically 1-100 μm spatial resolution (limited by laser spot size). **Why It Matters** - **Wafer Uniformity**: Maps composition and quality uniformity across full wafers (100-300 mm). - **LED/Laser Screening**: Identifies regions of optimal emission wavelength and intensity for device fabrication. - **Process Monitoring**: Non-destructive, rapid feedback on epitaxial growth uniformity. **PL Mapping** is **the optical uniformity inspector** — visualizing semiconductor quality and composition across entire wafers using luminescence.