In situ monitoring and benchmarking in UHV of InP/GaAsSb heterointerface reconstructions prepared via MOVPE

Thin InP layers were grown by metalorganic vapor phase epitaxy on the ternary compound GaAs0.5Sb0.5 lattice matched to InP(1 0 0). The heterojunctions were studied with in situ reflectance anisotropy spectroscopy and benchmarked in ultrahigh vacuum with ultraviolet and X-ray photoelectron spectroscopy and low energy electron diffraction with regard to the sharpness of the interface. During growth of GaAs0.5Sb0.5 an Sb-rich ð1 3Þ-like reconstruction was observed and during stabilization with TBAs an As-rich cð4 4Þ reconstruction. These two different reconstructions of GaAs0.5Sb0.5(1 0 0), well-known from the binaries GaSb(1 0 0) and GaAs(1 0 0) respectively, were used for preparing InP/GaAs0.5Sb0.5 heterojunctions. The RA spectra of thin heteroepitaxial InP layers were compared to a well-established RA spectrum of MOVPE-prepared homoepitaxial, ð2 1Þ-like reconstructed P-rich InP(1 0 0), that was used as a reference spectrum of a well defined surface. Growing InP on the cð4 4Þ reconstructed GaAsSb(1 0 0) surface resulted in a significantly sharper interface than InP growth on ð1 3Þ reconstructed GaAsSb(1 0 0).