Cathodo- and electro- luminescences image mapping technique to study traps in GaN-based LEDs

We have investigated the non-radiative recombination of GaN-based light-emitting diodes (LEDs) using electroluminescence (EL) and cathdoluminescence (CL) techniques. Comparing EL and CL measurements, we can map the defects causing non-radiative recombination centers. Also we have researched wet etch effect of Indium-Tin-Oxide (ITO) layer measuring CL technique. The more emissive region of EL measurement has the higher CL intensity in main band-edge (BE) peak in CL measurement, but the less emissive region also has lower CL intensity in BE peak and also defects-assisted emission peaks in other wavelengths and energy levels like yellow-luminescence (YL). It is concluded that the advantages of EL and CL image mapping of defects in GaN, establishing a strong correlation between the two techniques, should be very beneficial for further validation of the two techniques for GaN LEDs.