INGAAS INALAS INPLANE SUPERLATTICES GROWN ON SLIGHTLY MISORIENTED (110) INP SUBSTRATES BY MOLECULAR-BEAM EPITAXY/

InGaAs/InAlAs in-plane superlattices (IPSLs) composed of InAs/GaAs and InAs/AlAs monolayer superlattices were grown using molecular beam epi taxy. The substrates were misoriented (110) InP tilting 3 degrees towa rd the [00 $$($) over bar 1] direction. We grew half monolayers of AlA s and GaAs and single monolayers of InAs alternately, keeping regular arrays of single monolayer steps. The structures were evaluated by tra nsmission electron microscopy (TEM). In a transmission electron diffra ction pattern from the ($($) over bar$$ 110) cross-section, we observe d two types of superstructure spot pairs double-positioned in the [001 ] direction, indicating the formation of the intended IPSL structures. In a cross-sectional TEM dark-field image, we observed the InGaAs/InA lAs superlattice structures formed almost in the [001] direction. The mean period of the superlattices was approximately 4 nm, which was com parable to the terrace width expected from the substrate tilt angle. H owever, IPSL structures were not completely formed, i.e., the lateral interfaces meandered along the growth direction, and partial disorderi ngs were often observed. The photoluminescence spectrum from the IPSL had a peak corresponding to the InGaAs (2 nm thick)/InAlAs (2 nm thick )superlattice in addition to a peak corresponding to the In0.5Al0.25Ga 0.25As alloy.