In this paper, the influences of the graphite precursor and the oxidation method on the resulting reduced graphene oxide (especially its composition and morphology) are shown. Three types of graphite were used to prepare samples for analysis, and each of the precursors was oxidized by two different methods (all samples were reduced by the same method of thermal reduction). Each obtained graphite oxide and reduced graphene oxide was analysed by X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS) and Raman spectroscopy (RS).

The paper presents the results of investigations on resistance structures based on graphite oxide (GRO) and graphene oxide (rGO). The subject matter of the investigations was thaw the sensitivity of the tested structures was affected by hydrogen, nitrogen dioxide and carbon dioxide. The experiments were performed at a temperature range from 30 °C to 150 °C in two carrier gases: nitrogen and synthetic air. The measurements were also aimed at characterization of the graphite oxide and graphene oxide. In our measurements we used (among others) techniques such as: Atomic Force Microscopy (AFM); Scanning Electron Microscopy (SEM); Raman Spectroscopy (RS); Fourier Transform Infrared Spectroscopy (FT-IR) and X-ray Photoelectron Microscopy (XPS). The data resulting from the characterizations of graphite oxide and graphene oxide have made it possible to interpret the obtained results from the point of view of physicochemical changes occurring in these structures.

The paper presents analyses of current research projects connected with explosive material sensors. Sensors are described assigned to X and γ radiation, optical radiation sensors, as well as detectors applied in gas chromatography, electrochemical and chemical sensors. Furthermore, neutron techniques and magnetic resonance devices were analyzed. Special attention was drawn to optoelectronic sensors of explosive devices.

The paper deals with investigations concerning the construction of sensors based on a quartz crystal microbalance (QCM) containing a TiO2 nanostructures sensor layer. A chemical method of synthesizing these nanostructures is presented. The prepared prototype of the QCM sensing system, as well as the results of tests for detecting low NO2 concentrations in an atmosphere of synthetic air have been described. The constructed NO2 sensors operate at room temperature, which is a great advantage, because resistance sensors based on wide gap semiconductors often require much higher operation temperatures, sometimes as high as 500 °C. The sensors constructed by the authors can be used, among other applications, in medical and chemical diagnostics, and also for the purpose of detecting explosive vapours. Reactions of the sensor to nitroglycerine vapours are presented as an example of its application. The influence of humidity on the operation of the sensor was studied.

The paper presents the acoustic method for determining some parameters of fast surface states in semiconductors. This method uses the interactions of the phonon-electron type for determining both the effective carrier lifetime τ influenced by the fast surface energetic states and the velocity g of the carrier trapped by the surface states. Some experimental results of the parameters τ and g in near-surface region of real Si(111) samples for their various surface treatments, obtained by the offered method, are presented.

The possibility of using the transverse acoustoelectric phenomena in experimental investigations of near surface region in semiconductor crystals was discussed. The results of experimental investigations of GaP:Te (111) surfaces by means of the transverse acoustoelectric voltage were presented. Applying the transverse acoustoelectric voltage method, the lifetime τ of minority carrier in the near-surface region and the surface potential V s in GaP:Te(111) surfaces after their different technological treatments were determined.

Abstract. The paper presents a resistance structures with sensor layers based on nanostructures elaborated on the base of TiO2 and ZnO. The structures were tested concerning their sensitivities to the effects of nitrogen dioxide in the atmosphere of synthetic air. The TiO2 and ZnO nanostructures played the role of sensor layers. Investigations have proved that the elaborated resistance structures with TiO2 and ZnO layers are sensitive to the presence of NO2 in the atmosphere of synthetic air. The resistance of the structure amounted to about 20Ω in the case of ZnO structures and to about 200Ω in the case of TiO2 structures. The investigations confirmed that resistance structures with ZnO and TiO2, exposed to the effect of nitrogen dioxide in the atmosphere of synthetic air changes their resistances relatively fast. This indicates that such structures might be practically applied in sensors of nitrogen dioxide ensuring a short time of response.

The paper quotes the results of investigations concerning planar optical waveguides with a high value of the refractive index, achieved basing on a broad-band gap semiconductor ZnO, deposited on glass or quartz substrates. The investigations were focused on the properties of the waveguides, determining the modal characteristics, the attenuation coefficient and the structure of the surface.