CHEMISTRY AT THE AL- AND AU-ZNSE(100) INTERFACES

Core-level synchrotron-radiation photoemission spectroscopy was performed to examine the chemistry at Al/ZnSe(100) and Au/ZnSe(100) interfaces. The ZnSe layers were grown by molecular-beam epitaxy and the (100) surfaces were prepared by Se decapping. The metals were deposited on both Se-rich (2\ifmmode\times\else\texttimes\fi{}1) and Zn-rich c(2\ifmmode\times\else\texttimes\fi{}2) surfaces. The Al/ZnSe interface was found to be highly reactive and dominated by the formation of ${\mathrm{Al}}_{\mathit{x}}$${\mathrm{Se}}_{\mathit{y}}$, while the Au/ZnSe interface remained mostly unreactive and atomically abrupt. The stabilized Fermi-level positions for Al and Au on ZnSe(100) are 2.1 and 1.1 eV above the valence-band maximum, independent of doping type and initial surface composition.