Berlin 2005 – scientific programme

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O: Oberflächenphysik

O 38: Halbleiteroberfl
ächen und -grenzfl
ächen

O 38.2: Talk

Tuesday, March 8, 2005, 11:00–11:15, TU EB301

InP growth on c(4×4) and (1×3) reconstructed GaAsSb(100) surfaces — •Z. Kollonitsch¹, U. Seidel¹, S. Neumann², F.-J. Tegude², F. Willig¹, and T. Hannappel¹ — ¹Hahn-Meitner-Institut, SE 4, Glienicker Strasse 100, D-14109 Berlin — ²Universität Duisburg/Essen, Halbleitertechnik/Halbleitertechnologie, Lotharstr. 55, ZHO, Gebäude LT, D-47048 Duisburg

Lattice matched GaAs_0.5Sb_0.5/InP(100)-layers were grown by MOVPE at 770K. Contamination free sample transfer into ultrahigh vacuum (UHV) allowed for the correlation of in-situ reflectance anisotropy/difference (RA/RD) spectra with LEED and photoelectron spectra (XPS/UPS). The in-situ signals indicated that the GaAs_0.5Sb_0.5 surface was Sb-rich during growth and turned preferably into an As-rich surface after growth. The group-V rich surface reconstructions formed c(4×4) and (1×3) symmetries, which are well known from the related binaries GaAs and GaSb. Energy dependent UP spectra of the c(4×4) reconstruction showed a prominent peak near the valence band maximum which was attributed to a surface state. There were similarities between the c(4×4) reconstructed surfaces of GaAs_0.5Sb_0.5 and GaAs. XPS measurements of InP/GaAsSb interfaces taken in UHV and I-V curves of InP/GaAsSb resonant tunneling diodes indicated that Sb segregation into a subsequent InP layer was significantly lower when the InP film was grown on the c(4×4) reconstructed GaAs_0.5Sb_0.5 surface compared to the (1×3) reconstructed surface.