Abstract
In this work, the threading dislocation suppression effects of InAs/In0.52Al0.48As digital alloy intermediate layers in an InP-based InAlAs graded metamorphic buffer were investigated to improve the structural and optical qualities of the buffer. Cross-sectional transmission electron microscopy, atomic force microscopy, and photoluminescence measurements proved that the insertion of thin digital alloy layers in the graded buffer markedly improves the surface quality, decreases the threading dislocation density, and enhances the photoluminescence efficiency of In0.8Ga0.2As/In0.8Al0.2As quantum wells. This study shows great potentials by incorporating digital alloy intermediate layers in metamorphic buffers to improve the quality of metamorphic devices.