Bias dependence and correlation of the cathodoluminescence and electron beam induced current from an InGaN/GaN light emitting diode.

Micron-scale mapping has been employed to study a contacted InGaN/GaN LED using combined electroluminescence (EL), cathodoluminescence (CL), and electron beam induced current (EBIC). Correlations between parameters, such as the EBIC and CL intensity, were studied as a function of applied bias. The CL and EBIC maps reveal small areas, 2-10 μm in size, which have increased nonradiative recombination rate and/or a lower conductivity. The CL emission from these spots is blue shifted, by 30-40 meV. Increasing the reverse bias causes the size of the spots to decrease, due to competition between in-plane diffusion and drift in the growth direction. EL mapping shows large bright areas (~100 μm) which also have increased EBIC, indicating domains of increased conductivity in the p and/or n-GaN. [ABSTRACT FROM AUTHOR]