Cathodoluminescence measurements on green light-emitting GaP diodes

Green light-emitting GaP:N diodes (LED's) are investigated at room temperature using a scanning electron probe microanalyzer. Integral cathodoluminescence (CL) line scans across the p-n junction are carried out. The CL line scan is discussed in connection with the depth of the p-n junction and in comparison with the external quantum efficiency of the diodes. A higher concentration of non-radiative recombination centres are detected in some cases close to the p-n junction in the n-region. The injection ratio (under the forward-bias condition) is determined comparing CL with the electroluminescence.