A simple and reliable wafer-level electrical probing technique for III-nitride light-emitting epitaxial structures

We report an easy-to-implement wafer-level electroluminescence characterization technique for InGaN/GaN light-emitting diodes (LED's) epi-wafers by means of multiple electrical probes. By first damaging the p-n junctions of the LED epilayer at localized spots, diode-like current versus voltage characteristics and emission spectra can be obtained at injection currents as high as 100 mA. This allows a relative but reliable comparison of device-related parameters such as differential quantum efficiency, leakage current, and series resistance among LED epi-wafers.