Correlation between location of light emission and spatial Nitrogen distribution in GaP LED´s

Green-light-emitting diodes containing nitrogen only on the n side, the p side, and on both sides have been prepared by a single-step dissolution-regrowth liquid-phase epitaxial process with precisely controlled doping via the vapor phase. Because the ratios of total light emissions of the three diode types were 4:1:5, it is concluded that 80 percent of the light emission from diodes containing nitrogen on both sides is generated on the n side. This observation agrees with measurements of the lateral light output with high spatial resolution. A simple model for light generation in LED\´s is proposed which can be quantitatively analyzed using the measurements on our diodes and doping dependent material parameters from the literature. According to this model, the optimum doping levels are cm^-3and cm^-3, in agreement with empirical optimizations by other authors.