STRAIN RELAXATION PROCESS OF (INAS)(M)(GAAS)(N) STRAINED SHORT-PERIODSUPERLATTICES GROWN BY MOLECULAR-BEAM EPITAXY

The strain relaxation process and crystalline quality of (InAs)(m)(GaA s)(n) strained short-period superlattices (SSPSs) grown on a GaAs(001) substrate were investigated by transmission electron microscopy and d ouble-crystal X-ray diffraction. The lattice mismatch between the supe rlattice and the substrate was mainly accommodated by the generation o f misfit dislocations propagating parallel to the heterointerface with no threading dislocations. However, the density of misfit dislocation s was relatively low in the single SSPS heterostructure. Moreover, the full width at half-maximum of X-ray diffraction was markedly increase d with the generation of misfit dislocations. It was found that the re sidual strain of SSPS was effectively relieved by applying multiple SS PS heterostructures.