Cathodoluminescence assessment of GaAs1−x Px for light emitting diodes

The room temperature cathodoluminescence (CL) properties of selenium doped epitaxial layers of GaAs_1−xP_x, in the composition range 0·35 < x < 0.45, have been examined as a function of the Hall electron concentration. Material selected for this investigation had less than 2 per cent of the total CL emission in the i.r. For a fixed alloy composition the CL intensity is shown to increase with increasing electron concentration, while for a fixed electron concentration the intensity decreases with increasing GaP content. These results have been correlated with the electroluminescent efficiencies of zinc diffused diodes fabricated from the same material. It is shown that CL provides a rapid and reliable means of assessing the composition and emitting efficiency of epitaxial layers for use in the fabrication of light emitting diodes.