The arrangement of tungsten atoms (0.2-4 mono layers) evaporated onto W(llO) has been studied with LEED and work-function measurements in ultrahigh vacuum. For temperatures of T = 300-430 K island growth has been derived from rings, which are visible at characteristic energies, around each spot of the LEED pattern. By increasing substrate temperature the islands coalesce in the [001] direction. For T = 520--800 K the surface shows microfacets with step edges in the [1 TO] direction.Step-free epitaxial growth has been observed at T = 950 K. The decrease of work function during evaporation confirms the formation of islands and facets. The average dipole moment per edge atom has been determined by combination ofLEED and work-function data. Quantitative evaluation of the LEED pattern yields the distance between islands, size of islands, and number of rows of atoms per terrace. The results show that the LEED pattern provides information on epitaxial growth which is not available with any other technique.

Clean surfaces produced by cleavage or ion bombardment and annealing mostly show atomic steps. With a new derivation of the LEED pattern of a stepped surface it is now possible to predict and evaluate also the pattern of a surface on a non-primitive lattice. With the use of high precision LEED data depression of the edge atoms of about 0.25 Å is supported by several independent observations. On cleaved silicon and germanium surfaces the step density is determined for each spot of the surface. At clean cleaved silicon surfaces the photo surface voltage has been measured by scanning the surfaces with an electron beam. A correlation between the photo surface voltage and the angle of inclination of the respective spot of the surface towards the (111) face reveals the existence of one-dimensional surface states (“edge states”). It is therefore important to know the existence and properties of atomic steps on clean surfaces in both structural and electronic respects.

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Metal interactions with polyimides, studied so far by x-ray photoelectron spectroscopy (XPS), have shown surprising similarities. Dramatic changes are observed in the core levels associated with the carbonyl groups of the dianhydride portion of the polymer, in many cases already at submonolayer coverage, suggesting a high degree of selectivity. The nature of this reaction has been investigated by XPS and infrared spectroscopy comparing Cr/pyromellitic dianhydride-4,4′-oxydianiline (PMDA-ODA) with reduced polyimide films and electrochemical and Cs+ intercalation experiments. The results demonstrate conclusively that charge transfer occurs from metal atoms into the PMDA portion of the polymer at the initial stage of metal–polymer interaction. Hence subsequent metal–polymer compound formation involving bond breaking and displacement of O, N, and C from the polymer chain is seen as a logical consequence of the polymer preactivation by reduction.

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