Role of the substrate deoxidation process in the growth of strained InAs/InP heterostructures

We have investigated the role of the arsenic flux used during the substrate deoxidation process in the MBE (molecular beam epitaxy) growth of strained InAs/InP heterostructures. Two different experiments were performed: (i) thermal cleaning of the InP wafer under an As flux at different exposure times and (ii) the growth of very thin InAs layers (3-9 ML). The samples grown were characterized by Raman spectroscopy and selected area X-ray photoelectron spectroscopy. The results obtained demonstrated the formation of an InAsxP1-x sublayer at the interface of the InAs/InP system. The annealing of InP under an As flux promotes not only As --> P substitution on the surface, but also the subsequent diffusion of As atoms into the deeper subsurface region of InP.