PROJECT TITLE :

Fluorescence microscopy investigation of InGaN-based light-emitting diodes

ABSTRACT:

The authors image the spatial dependent luminescent properties of InGaN quantum wells (QWs) in light-emitting diodes (LEDs) using fluorescence microscopy with selective excitation of the QWs through the transparent sapphire substrate. The authors live strong carrier escape with the associated photovoltaic impact in the device below open and short circuit conditions. The addition of electrical contacts permits comparison of the images under both optical and electrical excitation. A lateral distribution of the junction potential is measured in LEDs with structured metal contacts. An ohmic contact creates an equipotential surface and influences the collective emission. The technique offers helpful insights into the spatial properties of the recombination processes in InGaN materials and LED fabrication processes at low forward bias.