Abstract: Scintillating CsI(Tl) films were obtained by vacuum deposition on single crystal- line LiF substrates and non-orienting glass substrates. Their structure and morphology were examined by X-ray diffraction and scanning electron microscopy. Scintillation properties of films dependent on their structure are discussed.

Abstract: This work was partially supported by the Basic Research Fund of Ukraine (Project No F7/310-2001).

Abstract: A thermodynamic model of the holographic recording process in photopolymers have been developed. By the example of photopolymerizing compositions PPC-488 containing oligoetheracrylates and neutral components (NC) we have explored dependencies of holographic characteristics of medium on NC concentration and thermodynamic properties of polymer-NC system. The thermodynamic affinity of the polymer forming during recording and NC was evaluated using the difference of their solubility parameters ∆δP,NC. We have determined the feasible range of variation for ∆δP,NC and optimal concentration of NC ( 0 opt N ) that ensure high-performance recording. It was ascertained that excess in NC concentration over the optimal value leads to the increase of photoinduced light scattering in the layer. The efficiency of scattering depends on the size of microphase enriched by NC. We have determined the size of microphase particles and its dependence on kinetic parameters of polymerization.

Abstract: . This paper discusses the results of the analysis and experimental characterization of a narrow bandpass optical filter based on the Fabry – Perot interferometer configuration with a variable spacing between the mirrors allowing for a relatively wide spectral tunability. Such a filter, with a high-throughput bandpass and sufficiently large aperture and acceptance angle, is of practical interest for a high-resolution spectrometry and remote sensing in the visible and infrared spectral regions. The Fabry – Perot filter (FPF) can be designed in a compact single-assembly architecture that can be accommodated within existing instruments and should provide a stable performance under variable thermal and mechanical conditions, including space and airborne platforms. Possible applications of the filter include high-resolution multi-spectral imaging, terrain mapping, atmosphere and surface parameters measurements, and detection of chemical and biological agents.

Abstract: The luminescence properties of the Rodamine 6G in strongly scattering matrix in dependence of the medium parameters were examined. The luminescence spectrum of this object was found to be dependent on the scattering particle concentration, particle material and sample thickness. It was shown that the main reason of the dependencies is an enhanced reabsorption of luminescence radiation in the light scattering sample caused by manifold light scattering.

Abstract: An overview of recent original results concerning self-organized pattern formation in the emission of bistable alternating current ZnS:Mn thin film electroluminescent structures (TFELS) as a dissipative system is given. The influence of technological factors, affecting the properties TFELS, and driving conditions on both the patterns and the hysteresis of the chargevoltage dependence that is responsible for bistability of the TFELS are considered. The correlation between patterns and the shape of the hysteresis is analyzed. The physical processes with positive and negative feedback, which serve, respectively, as activator and inhibitor in the given dissipative system, are discussed.

Abstract: New composite structures containing ZnS, CdS nanoparticles were prepared with bright light-blue colour of luminescence. The structures were formed by spraying organic solution of zinc or cadmium ditiocarbamate onto substrates at temperatures within the range 40…120°Ñ. It was established that the film emission maximum monotonously shifts into short-wave spectral region at the decreasing substrate temperature: from 590 nm (Òs = 120°Ñ) to 500 nm (Òs = 50°Ñ) for ZnS and from 510 nm (Òs = 120°Ñ) to 450 nm (Òs = 40°Ñ) for CdS. This fact can be explained by the quantum size effect: X-ray analysis has shown that researched films contain crystalline particles of 1…5 nm size.

Abstract: The influence of pulsed ruby laser irradiation on luminescence and optical transmission spectra of nominally undoped ZnO single crystals was investigated. Both treatment and measurements were performed at 300 K. The irradiation was found to cause the increase of crystal transmission in absorption edge region and the rise of shortwave wing of exciton luminescence with respect to its longwave one. These changes were accompanied with the rise of electric conductivity. The analysis of obtained results in common with earlier data led to the conclusion that the movement of mobile shallow donors from dislocations to crystal bulk took place under the influence of ultrasound wave excited by laser pulse. The decrease of shallow donor density near dislocations resulted in the shrinkage of c-band state density "tail" in these regions, which caused the shift of the optical absorption edge to the shortwave side.

Abstract: Characteristics of non-linear scattering of powerful pulses of Q-switched YAG:Nd3+ laser in an aqueous suspension of submicron-sized black-body particles has been investigated. Proposed is a model describing the results of experiments. This model involves laserinduced overheating of suspended particles and vaporization of surrounding water with subsequent rapid growth of vapor shells around the particles.

Abstract: Фiзика напiвпровiдникiв, квантова та оптоелектронiка = Semiconductor Physics, Quantum Elecnronics and Optoelectronics : International Scientific Journal / , Iн-т фiзики напiвпровiдникiв . – 1998 . – На англ. яз.

Abstract: . Present paper studies double barrier resonant tunnelling diodes (DB-RTD) based on GaN/AlGaN heterostructures, grown by plasma-assisted molecular beam epitaxy (PA-MBE). Tunnel (current-voltage, I (cid:150) V ) and capacitance (capacitance-voltage, C(cid:150)V ) spectroscopy meas- urements were performed at the temperature range from 4.2 to 300 K. It has been found that measured characteristics of DB-RTD have complex nonlinear behavior and reveal the current discontinuities of I (cid:150) V curves. The features can be explained by the existence of polarization fields and interface defects. These effects strongly influence on the potential profile of the DB- RTD heterostructures. To understand physics of the processes, numerical simulations of the given structures, using a model based on real-time Green(cid:146)s functions, have been performed. Comparative analysis of experimental and numerical data showed that the current instability and nonlinearity of characteristics of the nitride based DB-RTD can be connected with trap- ping the electrons onto interfacial and dislocation states in these heterostructures.

Abstract: The failings bound to the deterioration of the components under irradiations are complex and numerous. This paper describes the different kinds of radiations present in the space as well as their interactions with the materials composing the integrated circuits used in the spacecraft. Our survey will be focused on the Single Event Upset phenomenon induced by the passage of only one ionizing particle with applications on the Samsung SDRAM.

Abstract: Dissolution of CdTe and CdxHg1–xTe single crystals in solutions of H2O2– HCl–tartaric acid system has been studied. The surfaces of equal etching rates were constructed and the limiting stages of the dissolution process were ascertained. Also determined were the concentration limits for the solutions that can be used for chemical polishing the above-mentioned semiconductor materials.

Abstract: Abstract. CdTe thin films were grown on different substrates: BaF2 (111), polished Si (100), SiO2, bulk CdTe (110) and HgxCd1–xTe layers by hot wall epitaxy (HWE). Chosen temperature parameters and technological process of thin film fabrication provided the growth rate of about 0.03 mm/min. The current-voltage characteristics and transmission spectra were measured. X-ray diffraction data (XRD) measurements were carried out as well.

Abstract: Abstract. The spectra of a photoluminescence (PL) in plastically deformed (PD) ZnS:Mn single crystals are investigated. It is shown that the PD processes cause change of a quantitative ratio between separate types of glow manganese centres (MC) as a result of their local symmetry rearrangement. After decomposing of PL integral spectra by individual PL bands using the cumulative distribution Gauss function, the nature of a ratio change between PL MC of different types is established. The individual with the peaking in the range 618–620 nm is discovered.

Abstract: The diffusion of Phosphorus in silicon using a POCl3 source has been considered. In the base of Fair-Tsai model of P-diffusion an empirical equation for calculation of active diffused phosphorus density (Qel), is proposed. In this equation, a relationship between (Qel), diffusion time, temperature and junction depth of P-diffused layer (Xj), is presented. The value of sheet resistance (Rs), which is taken from theoretical determination at 900°C, has a good agreement with experimental result.

Abstract: Abstract. We propose the phenomenological description of ferroelectric disordering caused by charged defects in ferroelectric-semiconductors. The good agreement between the obtained experimental results for PZT films and theoretical calculations has been shown. We suppose that proportional to the averaged charge density s ρ of defects improper conductivity is sufficiently high to provide the screening of charge density random fluctuations δρs in the absence of external field. When external electric field ) ( 0 t E is applied, inner field fluctuations and induction fluctuations δD appear in the inhomogeneously polarized system “charged fluctuation + screening cloud”. We show that the macroscopic state of ferroelectric-semiconductor with random charged defects and sufficiently high improper conductivity can be described by three coupled equations for three order parameters. Averaged over sample volume induction D determines the ferroelectric ordering in the system, its square fluctuation 2 D δ determines disordering caused by electric field fluctuations appeared around charged fluctuations δρs, and s Dδρ δ reflects the correlations between the free carriers screening cloud and charged defects δρs. For the first time, we derive the following system of three coupled equations:

Abstract: Electrical and structural properties of Schottky-barrier diodes formed with TiBx and ZrBx amorphous layers on n-6H-, 15Rand 4H-SiC (with epi-layer) were studied. High thermal stability of ideality factors and barrier heights in the formed contacts was explained by the thermal stability of an interface TiBx(ZrBx)-SiC after rapid thermal annealing at 800°Ñ for 60 s.

Abstract: Results of investigation of the fine structure existing in emission spectra of the transverse-discharge pumped XeCl laser are presented. Influence of selective components of the cavity on the structure of spectrum of induced emission is investigated. Conditions of manifestation in the emission spectra of fine structure caused by the molecules rotation are clarified. Generation frequencies in the region of 0–3 transition are measured.

Abstract: High efficient holographic diffraction gratings with spatial frequencies from 600 to 3600 mm -1 have been recorded using As40S60-хSeх (х = 0, 10, 20) photoresist layers and He-Cd laser operating at the wavelength λ = 440 nm. The investigation of the grating relief made by atomic force microscopy revealed that As40S60-xSex resists allows one to record grating originals with profiles of various heights depending on the resist chemical composition, its etching and exposure times. We obtained typical spectral and angular dependences of the first order diffraction efficiency for the grating with the high modulation depth and groove profile close to the sinusoidal one. Comparing the recorded gratings with different spatial frequencies, exposure and etching times, we determined optimal recording conditions (exposure and etching times) in order to obtain gratings with the high diffraction efficiency.