Scanning electroluminescence microscopy: A powerful novel characterizationtool for light emitting diodes

A novel approach of spectrally resolved scanning electroluminescence micros copy is introduced as a powerful characterization tool directly imaging the spectral emission characteristics of luminescence:devices. This fast non-d estructive technique allows the direct correlation of morphological and opt ical properties of final devices at the microscopically identical sample po sition. it directly visualizes the inhomogeneities in epitaxial growth as w ell as in processing. Furthermore, it shows where and how much light and wi th which spectral characteristic is emitted by the device which is most imp ortant for device design, The characterization of an InGaN/GaN Light Emitti ng Diode is given as an example of the power of scanning electroluminescenc e microscopy. The luminescence intensity maps and the emission peak wavelen gth images are taken under-operation of the device. They directly image the optical quality of the device and yield direct images of the In fluctuatio ns with a spatial resolution of 1 mu m The indium concentration is found to fluctuate from 5% to 8%. The InGaN layer shows a strong spatially localize d emission characteristic.