Influence of high-index GaAs substrates on the growth of highly strained (InGa)As/GaAs heterostructures

A systematic study of the optical and microscopic properties of self-assemb led quantum dots in InxGa1-xAs/GaAs heterostructures has been carried out b y varying the In concentration and the (InGa)As layer thickness on both(1 0 0) and (3 1 1)B orientations. Photoluminescence spectroscopy indicates tha t the dot formation on high-index substrates is delayed at larger amount of (InGa)As with respect to (1 0 0) substrates for both moderate (x = 0.5) an d high (x = 1.0) lattice mismatch. Atomic force microscopy shows that consi stently smaller and flatter dots are obtained on high-index planes, highlig hting the important role played by substrate morphology on the dot self-agg regation process. (C) 1999 Elsevier Science B.V. All rights reserved.