High-spatial-resolution cathodoluminescence measurement of InGaN

This paper described observation of cathodolummescence (CL) of microcrystalline InGaN bulk crystals under a scanning electron microscope (SEM) with a high-spatia resolution (HR) CL measuring apparatus. HR-CL spectra from facets of InGaN crystals vary from facet to facet and are single peaked. Histogram analysis of the CL peak positions of HR spectra from the facets of the crystals in the area scanned during a lowresolution CL measurement shows a two-peaked form with comparable peak wavelengths. The diffusion length of a generated electron-hole pair or an exciton from the recombination centers with a higher-energ L level state to that with a lower state is estimated to be 500 nm at the longest by the comparison of two monochromatic HR-CL images of adjoining facets.