GROWTH MODES OF OVERLAYERS OF SE DEPOSITED ON CU(111) SURFACES

Growth modes of overlayers of Se deposited on Cu(111) surfaces have been studied by LEED, AES, TEM (transmission electron microscopy) and SEM (scanning electron microscopy). The Cu(111) surfaces are formed in situ by vacuum deposition on air-cleaved mica at 675 K in an ultra-high vacuum chamber. Overlayer characteristics are examined at a substrate temperature of 300 K. Auger signal versus nominal film thicknesses of Se curves consist of a few noticeable breaks and a plateau, which shows that the overlayer growth follows closely the mode of surface compound formation. Also, LEED and TEM results indicate that the surface compound formed on the Cu(111) surfaces is CuSe alloy with a lattice constant 3%-4% larger than that found for bulk CuSe crystal.