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The initial stage of formation of an organic coating of N,N′-bis(3-methylphenyl)-N,N′-diphenylbenzidine (TPD) on a crystalline (ZnO) surface in the course of thermal deposition in high vacuum has been studied using the low-energy total current spectroscopy technique. A change in the work function and the density of unoccupied electron states in an energy interval of 0–20 eV above the vacuum level was traced as the organic coating thickness increased up to 8 nm. The energy positions of the bands of unoccupied electron states in the TPD film have been determined, including π* band (7–9 eV above the Fermi level), σ1* band (10–12 eV), σ2* band (14–16 and 18–20 eV).

Unoccupied density of states (DOS) for the polar (0001) Zn, (000) O and non-polar (100) ZnO surfaces and for a MgO(001)-c(2 × 2) thin film were studied using total current spectroscopy (TCS). TC spectra of the ZnO surfaces reveal the Zn 4s-O 2p band (6.2 eV) and two DOS maxima in the Zn 4p-O 2p band which exhibited different energy positions on the Zn-terminated (8.1 eV) and O-terminated (11.0 eV) surfaces. In the TC spectra of the MgO thin film, the energy location of Mg-derived (8.0, 14.8 and 21.0 eV) and O-derived (11.6, 14.2 and 18.5 eV) maxima of DOS were determined. Previously reported data on DOS of these materials is discussed, and it is shown that additional detailed information on the energy structure of unoccupied DOS in ZnO and MgO in the 5-25 eV range above EF has been found.

Low energy electron diffraction, Auger electron spectroscopy, X-ray photoelectron spectroscopy and electron energy loss spectroscopy were used to study a process of electron beam evaporated deposition of magnesium oxide film on a strontium titanate substrate. An annealed substrate exhibited a SrTiO 3 (100)-(2×2) surface reconstruction and consisted of nearly equal areas of TiO 2 and SrO terminated planes (slightly rich TiO 2 ). A selective deposition of magnesium oxide onto TiO 2 terminated planes of strontium titanate substrate was carried out, and a formation of a MgO(100)-c(2×2) superstructure discovered. A plausible nature of the superstructure is discussed in terms of a non-stoichiometric MgO(100) plane with a 1/4 density of oxygen vacancies.

Thin copper oxide film formation on the polar ZnO(0001) and ZnO(0001) surfaces under ultra-high vacuum conditions was monitored by LEED, Auger, TCS and work-function measurements. The 2.5 nm thick discontinuous oxide films contained a mixture of CuO, Cu2O and ZnO. The effect of oxygen gas on the conductivity of the thin films has been measured, and a more pronounced increase of a relative resistance of the film is observed in the temperature range 400–500 K.

Laser-induced oxygen molecule desorption from crystalline (110) and compressed-powder rutile TiO 2 surfaces is investigated by time-of-flight distributions and desorption signal dependencies on laser fluence. A double-component distribution of desorbed O 2 molecules (a fast one and a slow one) justifies validity of both photoelectronic and thermo-activation mechanisms. The defected surfaces are characterized by the more intensive oxygen escape supporting the desorption flow formation via the surface defect sites.

Total current spectroscopy (TCS) was used to study an evolution of unoccupied states through the process of thin-layer copper deposition and its oxidation on polar ZnO(0001) and surfaces. Zn-derived and O-derived unoccupied bands were identified in the TC spectrum at 7.7 and 9.8 eV, respectively, from the clean and well ordered polar ZnO faces, while the spectra from a thin CuO layer reveal an intensive fine structure in the 6 - 25 eV energy range above the Fermi level, which is discussed in comparison with previously reported results of experimental and theoretical investigations. The obtained data provide additional information on the energy location of the edges of unoccupied bands in CuO in the 6 - 25 eV range relative to .

The formation of thin organic films of copper phthalocyanine (CuPc) deposited onto the surface of gold-coated quartz crystal resonator was studied in situ under ultrahigh vacuum conditions by means of total electron-beam-induced current spectroscopy in combination with deposit thickness determination by piezocrystal microbalance technique. Variations in the fine structure of the total current spectra of CuPc layers of var-ious thicknesses in the 0–8 nm interval have been analyzed and the electron mean free path in thin CuPc films was determined as a function of the electron energy. For electron energies of 5.0, 7.2, 14.4, and 18.0 eV above the Fermi level, the mean free path is 6.4, 3.9, 2.6, and 2.3 nm.

The paper reports the results on the interface formation of 5-10 nm thick conjugated layers of Cu-phthalocyanine (CuPc) with a number of solid surfaces: polycrystalline Au, (SiO(2))n-Si, ZnO(0 0 0 1), Si(1 0 0), Ge(1 1 1), CdS(0 0 0 1) and GaAs(1 0 0). The results were obtained using Auger electron spectroscopy (AES) and low-energy target current electron spectroscopy (TCS). The organic overlayers were thermally deposited in situ in UHV onto substrate surfaces. The island-like organic deposits were excluded from the analysis so that only uniform organic deposits were considered. In the cases of polycrystalline Au, Si(1 0 0) and Ge(1 1 1) substrates the AES peaks of the substrate material attenuated down to the zero noise level upon the increase of the CuPc film thickness of 8-10 nm. The peaks corresponding to oxygen atoms in the case of SiO(2) substrate, and to atoms from the ZnO, GaAs and CdS substrates were clearly registered in the AES spectra of the 8-10 nm thick CuPc deposits. The relative concentration of the substrate atomic components diffused into the film was different from their relative concentration at the pure substrate surface. The concentration of the substrate dopant atoms in the CuPc film was estimated as one atom per one CuPc molecule. Using the target current electron spectroscopy, it was shown that the substrate atoms admixed in the CuPc film account for the appearance of a new peak in the density of unoccupied electronic states. Formation of intermediate TCS spectra until the CuPc deposit reaches 2-3 nm was observed in the cases of GaAs(1 0 0), ZnO(0 0 0 1), Ge(1 1 1) surfaces. The intermediate spectra show a less pronounced peak structure different from the one typical for the CuPc films. It was suggested that the intermediate layer was formed by the CuPc molecules fully or partially decomposed due to the interaction with the relatively reactive semiconductor surfaces.

Results of the investigation into the interface formation during the deposition of the films based on aziridinylphenylpyrrolofullerene (APP-C60) up to 8 nm thick on the surface of the oxidized silicon substrate are presented. The procedure of detecting reflection of testing low-energy electron beam from the surface implemented in the total current spectroscopy mode with a change in the incident electron energy from 0 to 25 eV is used. The structure of maxima in the total current spectra induced by the APP-C60 deposited film is established, and the character of interrelation of these maxima with π* and σ* energy bands in the studied materials is determined. It is revealed due to analyzing the variation in intensities of the total current spectra of the deposited APP-C60 film and the (SiO2)n-Si substrate that the APP-C60 film is formed at the early deposition stage with the coating thickness thinner than one monolayer without the formation of the intermediate modified organic layer. As the APP-C60/(SiO2)n-Si interface is formed, the work function of the surface increases by 0.7 eV, which corresponds to the transfer of the electron density from substrate (SiO2)n-Si toward the film APP-C60. The optical absorption spectra of the APP-C60 films are measured and compared with the spectra of films of unsubstituted C60.

A double-component time-of-flight distribution of laser-desorbed CO 2 molecules was observed for a system of CO adsorbed on ZnO(0001). A strong increase of amount and a lowering of the threshold for the CO 2 desorption was caused by a submonolayer deposition of Cu.

Recent results of surface electronic and geometrical properties of ultrathin copper layers on the crystalline metal-oxide substrates TiO2(110), α-Al2O3(0001), CaO(001), ZnO(1120) and ZnO(0001) are reviewed. The basic experimental data of interest have been obtained by using LEED, AES, PES and EELS. New experimental results on laser-induced desorption (LID) from the system C0/Cu/ZnO(0001) are presented.