EXTREMELY UNIFORM IN0.08GA0.92AS GAAS SUPERLATTICE GROWN ON A (411)A GAAS SUBSTRATE BY MOLECULAR-BEAM EPITAXY/

An In0.08Ga0.92As/GaAs strained-layer superlattice (SLS) grown on a (4 11)A GaAs substrate by molecular beam epitaxy (MBE) was characterized by high resolution X-ray diffraction (HRXRD) and low-temperature photo luminescence (PL) measurements. The (411)A InGaAs/GaAs SLS exhibited m uch narrower 0th and +/-1st HRXRD peaks compared with those of an InGa As/GaAs SLS simultaneously grown on a (100) GaAs substrate, which is m ainly due to the difference of fluctuation of tilting angles of local crystal planes in the SLSs. This fluctuation of the (100) InGaAs/GaAs SLS was caused by a considerable amount of relaxation of lattice-misma tch between InGaAs and GaAs layers. There was no such relaxation in th e (411)A InGaAs SLS. Furthermore, a higher PL intensity and a smaller PL linewidth of the (411)A SLS were also observed compared with those of the (100) SLS. These results indicate that the (411)A InGaAs/GaAs S LS has a much improved crystalline quality compared with that of the c onventional (100) InGaAs/GaAs SLS. (C) 1998 Elsevier Science Ltd. All rights reserved.