Photoluminescence study of the strain relaxation of GaAs crystals grown on deeply patterned Si substrates

We report on thermal strain relaxation in heteroepitaxial three dimensional crystals of GaAs grown on deeply patterned Si(001) substrates. The relaxation of the thermal strain induced by the three dimensionality and micrometric size of the GaAs crystals is investigated by comparing different pattern geometries. We exploit photoluminescence measurements to accurately evaluate the amount of residual strain. Our results confirm that deep substrate patterning is an effective way to relax the thermal strain of heteroepitaxial GaAs/Si.