The results of a study of unoccupied electronic states and the formation of a boundary potential barrier during thermal vacuum deposition of ultrathin films of 4-quaterphenyl oligophenylene on the surface of CdS and on the surface of oxidized silicon are presented. Using X-ray photoelectron spectroscopy (XPS) it was determined, that the atomic concentrations of Cd and S were equal in the surface layer of a 75-nm-thick CdS film formed by atomic layer deposition (ALD). The electronic properties of 4-quaterphenyl films up to 8 nm thick were studied during their deposition on the surface of the CdS layer and on the surface of oxidized silicon using total current spectroscopy (TCS) in the energy range from 5 eV to 20 eV above EF. The energetic position of the main maxima of the fine structure of the total current spectra (FSTCS) of 4-quaterphenyl films was determined. The location of the maxima was reproducible when two selected substrate materials were used. A minor decrease in the work function, from 4.2 eV to 4.1 eV, was registered during the thermal deposition of 4-quaterphenyl onto the CdS surface. During the deposition of a 4-quaterphenyl film on the oxidized silicon surface, an increase in the work function from 4.2 eV to 4.5 eV was found. Possible mechanisms of the physicochemical interaction between the 4-quaterphenyl film and the surface of the investigated substrates, which lead to a difference in the observed values of the work function of the films on these substrates, are discussed.

The morphology of organic semiconductor films of perylenetetracarboxylic acid dianhydride (PTCDA) and perylenetetracarboxylic acid dibenzyl-diimide (N, N`-DBPTCDI) formed by thermal vacuum deposition was studied by atomic force microscopy. It was shown that annealing of films at 420 K leads to rearrangement of their structure and crystallization. The optical absorption spectra of the films under study were used to estimate the optical band gap. The temperature dependence of the dark conductivity of PTCDA and N, N-DBPTCDI films before and after annealing (Т = 420 K) was established. The values of the activation energy of charge carrier traps are determined. The computer simulation of the density of localized states in the band gap of the films studied was carried out using the photoconductivity spectra in the constant photocurrent mode. Model photovoltaic cells based on PTCDA / СuPc and N, N-DBPTCDI / СuPc structures were formed. The kinetics of decay of the interfacial photo-voltage of the cells prepared was measured using pulsed light as an excitation source. On the basis of the performed measurements, the charge carrier mobility values in the investigated semiconductor materials were estimated.