Experimental study of electroluminescence and temperature distribution in high-power AlGaInN LEDs & LED matrixes

Comprehensive analysis of current spreading, temperature distribution, and near-field electroluminescence of high-power “face-up” AlInGaN LEDs and LED matrixes been performed by combination of different experimental and methods. A thermal resistance characterization consists in investigations of transient electrical processes in the diode sources under heating by direct current and analysis using a thermal equivalent circuit (the Cauer model). By the involved method, thermal resistances of internal elements of the LEDs are determined. At the same time high resolution mapping of EL and thermal radiation was obtained by optical microscope and infra-red images technique. It has been established correlation of the thermal resistance with a change in the current distribution at high excitation levels (current crowding).