Correlation of Defect-Impurity Interactions in GaP with Local Variations in Photoluminescence

Abstract
A direct correlation between small-scale spatial inhomogeneities in the photoluminescent efficiency of GaP LEC wafers and local variations in the density of shallow saucer-shaped chemical etch pits has been made. These variations are particularly evident in the vicinity of dislocations, suggesting that the dislocations act as a sink for the impurity or crystal defect responsible for the formation of saucer pits. In addition, larger-scale spatial variations in PL efficiency and saucer-pit density, believed to be related to the LEC crystal-growth procedure, are mirrored in the contrast obtained on Borrmann x-ray topographs.