High quality InP epilayers grown on GaAs substrates using metamorphic AlGaInAs buffers by metalorganic chemical vapor deposition

Using compositionally step graded metamorphic AlGaInAs buffers with a thickness of 2.4 μm, we grow InP epilayers on GaAs substrates with miscuts of 2°, 7°, and 15° toward (111)A by metalorganic chemical vapor deposition. The InP top layer is almost strain-free and its quality depends on the substrate miscut. Strong phase separation in AlGaInAs buffers is observed in the 2° sample, while it is suppressed in 15° sample. Finally, a higher crystalline quality InP epilayer with a root-mean-square roughness of 10.1 nm is obtained on 15° substrate as confirmed by a much stronger photoluminescence peak intensity of the InP epilayer on 15° substrate compared with those on 2° and 7° substrates. Growth of high quality InP on GaAs opens up the possibility of integrating GaAs and InP based devices, and will greatly enhance the functionality of devices grown on GaAs substrates.