(GA0.22IN0.78AS)M/(GA0.22IN0.78P)M SUPERLATTICES GROWN BY ATOMIC-LAYER MOLECULAR-BEAM EPITAXY ON INP

Strained-layer superlattices (SLSs) made up of alternated GaxIn1-xAs and GaxIn1-xP, with x =0.22 is an alternative to the quaternary GaxIn1-xAsyP1-y. Strain is near symmetrized when grown on InP substrates. Lattice mismatch to InP (-1.57% GaInP, 1.71% GaInAs) being compensated, the net value of strain in the SLS is expected to be negligible. Using low temperature atomic-layer MBE (T(s) = 350-degrees-C), P2 and As4 are supplied in successive pulses to group III terminated intermediate surfaces, minimizing competition, by using specially designed, fast operating valved solid source cells. A set of (Ga0.22In0.78 As)m/(Ga0.22In0.78P)m superlattices have been grown, with m ranging from 1 to 10 monolayers. The samples were characterized by X-ray diffraction. Photoluminescence measurements were performed, at 98 and 300 K, the emission wavelength ranging from 1.27 to 1.52 mum at room temperature. These superlattices have been used as pseudoquaternary material in InP/GaInAsP/GaInAs structures emitting at 1.5 mum.