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

Wallace, M. J. and Edwards, P. R. and Kappers, M. J. and Hopkins, M. A. and Oehler, F. and Sivaraya, S. and Allsopp, D. W. E. and Oliver, R. A. and Humphreys, C. J. and Martin, R. W. (2014) Bias dependence and correlation of the cathodoluminescence and electron beam induced current from an InGaN/GaN light emitting diode. Journal of Applied Physics, 116 (3). 033105. ISSN 0021-8979

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    Abstract

    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.