Growth initiation and cathodoluminescence irregularities in LPE AlGaAs layers

In a previous publication, we described the occurrence of a patchy contrast in cathodoluminescence (CL) images of thin LPE layers of AlGaAs grown on Cr‐doped GaAs substrates. The present paper, a continuation of that work, reports on CL observations of LPE AlGaAs layers grown on Si‐doped GaAs substrates and on freshly grown Sn‐doped LPE layers; in addition, we have examined changes in the CL intensity distribution with layer thickness. It is concluded that the ’’patches’’ are confined to a region near the GaAs‐AlGaAs interface, and that their appearance is associated with the initiation of the AlGaAs epilayer growth.