ELECTRON-ENERGY LOSS AND AUGER-SPECTROSCOPY OF THE YB-GAP(110) INTERFACE

The Yb-GaP(110) interface formation was studied by EELS (electron energy loss spectroscopy) and AES (Auger electron spectroscopy). The EELS was performed in the 2-27 eV loss range at different coverages ranging from 0.5 to 20 ML (monolayer) with a primary beam energy of 100 eV. Losses typical of the interface were found at approximately 3.5 and 6 eV. The EEL data are characterized by the persistence of the 20 eV loss associated with the Ga 3d level. The AES P L2,3VV data were taken at 1 and 2 ML as a function of the take-off angle. Lineshape changes were observed both versus coverage and versus angle, allowing insight into the bonding at the P site versus coverage and depth. A model of the morphology of the interface during the growth process is presented characterized by Yb-P compounds formation and Ga segregation at the surface.