Characterization of gallium arsenide phosphide light‐emitting diodes by photoluminescence

The use of spectrally and spatially revolved photoluminescence for investigation of GaAs0.6P0.4 light‐emitting diodes is described. A HeCd laser focused to 8 μm was used for excitation. Photoluminescence spectra were taken at 95 and 300 K. They show distinct differences between the p‐type junction area and the n‐type substrate region. Devices with a different electroluminescence efficiency showed corresponding differences in their photoluminescence behavior. The p‐n junction depth was found to be a critical parameter, influencing electroluminescence as well as the photoluminescence spectra. Spectrally resolved photoluminescence can be used as a tool to characterize light‐emitting diode materials and devices at different production stages.