AUGER-ELECTRON SPECTROSCOPY, LOW-ENERGY-ELECTRON DIFFRACTION AND ELECTRON-ENERGY-LOSS SPECTROSCOPY STUDIES OF SE OVERLAYERS GROWN ON CU(111) SURFACES

The surface alloying and film growth processes of Se overlayers deposited on Cu(111) surfaces have been investigated using in situ Auger electron spectroscopy (AES), low energy electron diffraction (LEED) and electron energy loss spectroscopy (EELS) at a substrate temperature of 300 K. The Cu(111) substrate was formed in situ by vacuum deposition on air-cleaved mica at 675 K in an ultrahigh vacuum chamber. AES results can be interpreted by assuming the growth mode of surface compound formation. In EELS, the energy loss from Cu surface changes gradually with Se deposition, and a new loss at 13.0 eV appears. Also, in LEED, the intensity and position of extra spots indicating the surface structure of overlayers change drastically with Se deposition. These results indicate that the surface compound formed on Cu(111) surfaces is Cu-Se alloy and that the alloying is started immediately after the completion of the Cu(111) ((3 1/2 x 3 1/2) R30-degrees)-Se structure.