(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 a nd GaxIn1-xP, with x =0.22 is an alternative to the quaternary GaxIn1- xAsyP1-y. Strain is near symmetrized when grown on InP substrates. Lat tice mismatch to InP (-1.57% GaInP, 1.71% GaInAs) being compensated, t he 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 ar e supplied in successive pulses to group III terminated intermediate s urfaces, minimizing competition, by using specially designed, fast ope rating valved solid source cells. A set of (Ga0.22In0.78 As)m/(Ga0.22I n0.78P)m superlattices have been grown, with m ranging from 1 to 10 mo nolayers. The samples were characterized by X-ray diffraction. Photolu minescence measurements were performed, at 98 and 300 K, the emission wavelength ranging from 1.27 to 1.52 mum at room temperature. These su perlattices have been used as pseudoquaternary material in InP/GaInAsP /GaInAs structures emitting at 1.5 mum.