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Amorphous silicon carbide is known as a material resistant except others influences also against radiation. This study investigates the effects of neutron radiation on electric characteristics (I-V characteristic, impedance spectra and obtained dynamic parameters of AC equivalent circuit) of solar cell a-SiC/c-Si heterojunction structure. The heterojunction structure was irradiated using neutrons with neutron fluence 1013 cm-2. Existence of neutron induced structural defects, which could be introduced within semiconductor structure of heterojunction, has been illustrated using DC and AC analysis. The structural defects induced by neutron particles radiation affect mainly trapping mechanism. The process results in the changes of electronic elements included into proposed equivalent circuit.

The paper presents fabrication and characterization of amorphous silicon carbide (a-SiC:H) based structures for photo-electrochemical (PEC) water splitting. The increase of the photocurrent of PEC upon the decreased of CH4 flow during the deposition is associated with the decrease of the band gap and increased absorption of light in a-SiC:H. Photocurrent of 50 µA/cm2 is achieved for PEC structure prepared with the lowest CH4 flow during the deposition. An ITO/a-SiC:H/Si silicon heterojunction structure forming a simple photovoltaic cell (PV) with efficiency of 9.66% was prepared to support additional voltage hereby forming a hybrid PEC-PV system. ASA simulation revealed that a photocurrent of 0.62 mA/cm2 and solar to hydrogen efficiency of 0.76% can be achieved for hybrid a PEC-PV structure with 5 PVs connected in series behind the PEC cell. Further opportunities for increasing the performance are discussed and summarized.

A prototype of a direct-current photoinjector (DC) with an electron energy of up to 400 keV is being developed at JINR for future electron accelerators (electron-positron colliders and free-electron lasers). This article describes the injector, one distinctive feature of which is the use of the transmission photocathode operation mode. A unique laser system is implemented on the photoinjector. The system makes it possible to synchronize the repetition rate and the phase of the laser pulses (of 10 ps duration, 262 nm wavelength, and 1.85 μJ energy) with the frequency of the accelerator RF system. The first experimental results of a DC photoinjector are presented and further plans for the development of the installation are discussed.

Boron-doped SiC thin films were deposited on N-type Si(100) substrates at various deposition conditions by means of HWCVD technology using silane (SiH4), methane (CH4), hydrogen(H2), dibora...

A photoinjector prototype for future electron–positron colliders and free-electron lasers (FEL) is being developed at the Joint Institute for Nuclear Research (JINR). A 30-keV photogun stand, transmission (backside irradiated) photocathode concept, and stand investigations of such cathodes in collaboration with Institute of Electrical Engineering (IEE SAS) (Bratislava, the Slovak Republic) are described. A progress report on creating the photoinjector at an electron energy of up to 400 keV with a unique 10-ps laser driver is given.

This paper presents results of the development of silicon heterojunction solar cells with a front high band gap amorphous silicon carbide emitter. The attention is focused on the optimization of deposition conditions of sputtered ITO. For the comparison as an alternative also IZO transparent conduction oxides (TCO) were prepared and measured. ITO (IZO) are key layers to attain good antireflection and collection properties. It is shown that sputtering current affects both optical as well as electrical properties of prepared ITO. Complex electrical characterization of prepared solar heterostructures was performed by using DC and AC techniques. Measurements were performed under the dark and light conditions. The obtained results show the usefulness of complementary approach in order to assess the behavior of measured samples. The best efficiency of 9.66 % is attained with ITO layer deposited at low sputtering current.

The cosmological lithium problem, that is, a noticeable discrepancy between the predicted and observed abundances of lithium, is in conflict with the Standard Big Bang Nucleosynthesis model. For example, the abundance of 7Li is 2–4 times smaller than predicted by the Standard Big Bang Nucleosynthesis. As to the abundance of 6Li, recent more accurate optical investigations have yielded only the upper limit on the 6Li/7Li ratio, which makes the problem of 6Li abundance and accordingly of disagreement with the Standard Big Bang Nucleosynthesis predictions less acute. However, experimental study of the D(4He, γ)6Li reaction cross section is still of current importance because there is a theoretical approach predicting its anomalously large value in the region of energies below the Standard Big Bang Nucleosynthesis energy. The work is dedicated to the measurement of the cross section for the D(4He, γ)6Li reaction proceeding in zirconium deuteride at the incident 4He+ion energy of 36 keV. The experiment is performed at a pulsed Hall plasma accelerator with an energy spread of 20% FWHM. A method for direct measurement of the background from the reaction chain D(4He, 4He)D→D(D, n)3He→(n, γ) and/or (n, n′γ) ending with activation of the surrounding material by neutrons is proposed and implemented in the work. An upper limit on the D(4He, γ)6Li reaction cross section σ≤7·10−36 cm2 at the 90% confidence level is obtained.

The cross section of the reaction D(4He, γ)6Li with titanium and zirconium deuterides as targets is measured for incident 4He+ ion energies of 30 and 36 keV, respectively. The ion beam is generated by a Hall pulsed plasma accelerator. For the first time, upper limits on the cross section of the reaction D(4He, γ)6Li at ultralow energies are imposed (at 90% confidence level): σ ≤ 1.2 × 10−35 cm2 for the TiD2 target and E(4He+) = 30 keV, and σ ≤ 7 × 10−36 cm2 for the ZrD2 target and E(4He+) = 36 keV

Investigation of the pd-and dd-reactions in the ultralow energy (~keV) range is of great interest in the aspect of nuclear physics and astrophysics for developing of correct models of burning and evolution of stars. This report presents compendium of experimental results obtained at the pulsed plasma Hall accelerator (TPU, Tomsk). Most of those results are new, such as • temperature dependence of the neutron yield in the D(d, n)3He reaction in the ZrD2, Ta2D, TiD2 • potentials of electron screening and respective dependence of astrophysical S-factors in the dd-reaction for the deuteron collision energy in the range of 3–6 keV, with ZrD2, Ta2D temperature in the range of 20–200°C [1] • characteristics of the reaction d(p, γ)3He in the ultralow collision proton-deuterons energy range of 4-13 keV [2, 3] in ZrD2, Ta2D and TiD2 • observation of the neutron yield enhancement in the reaction D(d, n)3He at the ultralow deuteron collision energy due to channeling of deuterons in microscopic TiD2 with a face-centered cubic lattice type TiD1.73, oriented in the [100] direction [4]. The report includes discussion and comparison of the collected experimental results with the global data and calculations.

Very thin N-doped nanostructured carbon films were deposited on quartz and sapphire substrate by radio-frequency reactive magnetron sputtering using carbon target and gas mixture of Ar and N2 or N2+H2 reactive gasses. Rutherford backscattering spectroscopy and Elastic recoil detection analytical methods determined the concentration of elements in the films. Scanning electron microscopy was used to investigate the surface morphology of nanostructured very thin carbon films. Raman spectroscopy was used for the determination of chemical structural properties of the thin nanostructured carbon films. Pulsed laser induced electron emission method was used for the study of photoelectron emission properties of nanostructured carbon films. Measured bunch charge results of fabricated transmission photocathodes showed better photoelectron emission properties of very thin nanostructured carbon films prepared on sapphire substrates. Effects of substrate and technology of very thin nanostructured carbon films on the properties of photo-induced electron emitters as backside illuminated transmission photocathode are discussed.

Very thin carbon-based nitrogen-doped films of different thicknesses were deposited on double-side polished sapphire substrates by RF reactive magnetron sputtering. RBS and ERD were used to determine the elemental concentration in the films, and Raman spectroscopy, to determine their chemical structure. The RBS and ERD analyses indicated that the films contained carbon, nitrogen and small amounts of hydrogen and oxygen. The Gaussian-fitted and identified Raman spectra of the films showed the D and G bands in the range 1000-1800 cm−1, and the 2 D and D+G bands, in the range 2500-3100 cm−1. The photo-induced (pulsed laser, 266 nm) electron emission properties of the films were determined by measuring the cathodes’ bunch charge and calculating their quantum efficiency. The paper discusses the structural properties of the very thin nitrogen-doped carbon-based films deposited on a sapphire substrate with different thicknesses in view of their use as backside-illuminated transmissive vacuum photocathodes.

The carbon-based very thin films were deposited on silicon substrate and double side polished sapphire or quartz glass by RF reactive magnetron sputtering using a carbon target and gas mixtures Ar, N2 and H 2. Concentration of elements in the films was determined by RBS and ERD method simultaneously. SEM was used to investigate the morphology of carbon thin films. Raman spectroscopy was used for intensity ratios determination I(D)/I(G) of D and G peaks of carbon films. Photo-induced electron emission method was used for the study of electron emission properties of carbon-based very thin films. An examination of the results highlights how the technology and the structure of carbon films on quartz or sapphire glass play a key role in enhancing efficient escape of generated photoelectrons.

This work is dedicated to measuring the dependences of the effective cross section and the astrophysical S factor for the pd reaction that proceeds in zirconium deuteride upon the proton-deuteron collision energy within a range of 6.0–23.3 keV. The experiment was performed using the heavy-current plasma Hall accelerator at the National Research Tomsk Polytechnic University. The gamma quanta produced in the pd reaction with the energy of 5.5 MeV was recorded using eight scintillation spectrometers based on NaI(Tl) crystals (400 × 100 × 100 mm), which were located around the target. The result of this work coincides with the result of our previous work obtained within a range of proton-deuteron collision energies of 7.3–12.7 keV and agrees well with the result obtained by the LUNA collaboration with the use of the gaseous deuterium target.

Interest in amorphous silicon and carbon alloys is always actual mainly due to their particular advantages in comparison to conventional crystalline materials. The amorphous silicon carbide may be used in a number of micro-mechanical and micro-electronics applications and also for photovoltaic energy conversion devices. Boron doped thin layers of amorphous silicon carbide, presented in this paper, were prepared due to the optimization process for preparation of heterojunction solar cell. DC and AC measurement and subsequent evaluation were carried out in order to comprehensively assess the electrical transport processes in the prepared structures.

Energy dependence of the neutron yield from the d ( d , n ) 3 He reaction in a textured target of titanium deuteride with predominant [1 0 0] orientation of microcrystals is investigated. The measurements were performed for the incident deuteron energies ranging from 7 to 12 keV in the laboratory coordinate system. It is shown that the energy dependence of the enhancement factor is described not only by the screening potential but also by simply taking account of channeling effects.

Characteristics of the pd reaction (p + d → 3He + γ(5.5 MeV)) in titanium deuteride at astrophysical proton-deuteron collision energies ranging from 5.3 to 10.5 keV are investigated. Experiments are conducted on the pulsed plasma Hall accelerator at Tomsk Polytechnic University (Tomsk, Russia). The number of accelerated protons in a pulse 10 μs long is 5 × 1014 at a repetition rate of 7 × 10−2 Hz. Gamma rays with an energy of 5.5 MeV are recorded by eight detectors based on NaI(Tl) crystals (100 × 100 × 400 mm) arranged around the TiD target. The dependence of the astrophysical S factor for the pd reaction on the proton-deuteron collision energy and the electron screening potential of protons interacting with deuterons in titanium deuteride are measured for the first time.

The article is devoted to the investigation of a pd-reaction (p + d → 3He + γ(5.5 MeV)) under-going in titanium deuteride in astrophysical collision energy region of protons and deuterons ranging from 5.3 to 10.5 keV. The experiments have been performed using the Hall NR TPU (Tomsk, Russia) pulsed plasma accelerator. The number of accelerated protons in 10 μs pulse was 5 × 1014 at a repetition rate of 7 × 10−2 Hz. Detection of 5.5 MeV gamma rays was carried out using eight detectors based on crystals of NaI(Tl) (100 × 100 × 400 mm) placed around the TiD target. For the first time, the dependencies between the astrophysical S-factor and the effective cross section of the pd-reaction from proton-deuteron collision energy, and the potential electronic screening of the interacting protons and deuterons in titanium deuteride have been measured.

In this study we report on the dependence of electron emission properties on the transmission photocathodes DC gun based on stainless steel mesh coated with diamond like carbon films prepared at various technological conditions. Diamond like carbon films were deposited on the stainless steel mesh and silicon substrate by plasma enhanced chemical vapor deposition from gas mixtures CH 4 +D 2 +Ar, CH 4 +H 2 +Ar and reactive magnetron sputtering using a carbon target and gas mixtures Ar+D 2 , Ar+H 2 . The concentration of elements in films was determined by Rutherford backscattering spectrometry (RBS) and elastic recoil detection (ERD) analytical methods simultaneously. Chemical compositions were analyzed by Fourier transform infrared spectroscopy (FT-IR). Raman spectroscopy at visible excitation wavelength was used for the intensity ratio determination of Gaussian fit D-peak and G-peak of Raman spectra. The quantum efficiency was calculated from the measured laser energy and the measured cathode charge. The quantum efficiency of a prepared transmission photocathode was increased with increasing intensity ratio of D-peak and G-peak, which was increased by adding deuterium to the gas mixture and using technology reactive magnetron sputtering.

The article is devoted to the investigation of a pd -reaction ( p + d → 3 He+ γ (5.5 MeV)) undergoing in titanium deuteride in astrophysical collision energy region of protons and deuterons ranging from 5.3 to 10.5 keV. The experiments have been performed using the Hall NSR TPU (Tomsk, Russia) pulsed plasma accelerator. The number of accelerated protons in 10 μs pulse was 5×10 14 at a repetition rate of 7×10 −2 Hz. Detection of 5.5 MeV gamma rays was carried out using eight detectors based on crystals of NaI(Tl) (100×100×400 mm) placed around the TiD target. For the first time, the dependencies between the astrophysical S -factor and the effective cross-section of the pd -reaction from proton to deuteron collision energy, and the potential electronic screening of the interacting protons and deuterons in titanium deuteride have been measured.

The energy dependence of the neutron yield in the d(d, n)3 He reaction proceeding in a textured titanium deuteride target with the preferred orientation of microcrystals in the [100] direction has been studied. Measurements have been performed for the energy range of incident deuterons of 7–12 keV in the laboratory system. It has been shown that the energy dependence of the enhancement factor of the reaction is described not only by the screening potential but also by the simple inclusion of channeling effects.

The amorphous silicon carbide/crystalline silicon heterojunction was prepared and analyzed. The current-voltage (I − V ) measurements showed the barrier properties of prepared sample. Biased impedance spectra of Al/a-SiC/c-Si(p)/Al heterojunction under the standard illumination are reported and analyzed. AC measurements in the illuminated conditions were processed in order to identify electronic behavior using equivalent AC circuit which was suggested and obtained by fitting the measured impedance data. A phenomenon of negative capacitance/resistance in certain frequency range has been observed. K e y w o r d s: PECVD, heterojunction, silicon carbide, equivalent AC circuit, complex impedance

Phosphorus doped silicon carbide film as emitter in heterojunction structure was deposited on p-type Si(100) wafers at various deposition conditions by means of PECVD technology using silane (SiH4), methane (CH4), hydrogen (H2) and phosphine (PH3, 2 vol.% in H2) gas as precursors. ITO or IZO film was RF magnetron sputtered on top of the different P doped a-SiC:H(n) film. Irradiation of structures with Xe ions to total fluency 5×1011 cm−2 was performed at room temperature. Influence of phosphorus concentration and type of transparent conducting oxide was investigated. A deeper insight on the impact of irradiation on the electrophysical properties of sample was obtained by the analysis of complex impedance spectra.

Silicon carbide (SiC) and nitrogen-doped silicon carbide (SiC(N)) films were deposited on p-type Si(100) substrates at various deposition conditions by means of plasma-enhanced chemical vapor deposition (PECVD) technology using silane (SiH4), methane (CH4), and ammonia (NH3) gas as precursors. The concentration of elements in the films was determined by Rutherford backscattering spectrometry (RBS) and elastic recoil detection (ERD) analytical method simultaneously. Chemical composition was analyzed by Fourier transform infrared spectroscopy (FT-IR). The films contain a small amount of oxygen. IR results showed the presence of SiC, SiN, SiH, CH, CN, NH, and SiO bonds. The current–voltage (I–V) characteristics of samples before and after neutron irradiation were measured. The measured current increases after irradiation with neutrons.

Amorphous silicon carbide (a-SiC) is an excellent alternative passivation layer material for silicon solar cells especially working in hard and space environment. Silicon carbide (SiC) and nitrogen-doped silicon carbide (SiC(N)) layers were deposited on P-type Si(1 0 0) substrates at various deposition conditions by means of plasma enhanced chemical vapor deposition (PECVD) technology using silane (SiH 4 ) methane (CH 4 ) and ammonium (NH 3 ) gas as precursors. The concentration of elements in layers was determined by Rutherford backscattering spectrometry (RBS) and elastic recoil detection (ERD) analytical method simultaneously. Chemical compositions were analyzed by Fourier transform infrared spectroscopy (FT-IR) and Raman spectroscopy. Irradiation of samples by fast neutrons with fluence 1.4 × 10 14 cm −2 was used. No significance effect on the IR spectra band features after neutron irradiation was observed. Intensity of Raman spectra band features was decreased after neutron irradiation. The measured currents after irradiation are greater (up to 100 times) than the current before irradiation for all samples.

Amorphous silicon carbide films were prepared by PECVD technology on Si substrate with the aim to use SiC films in the technology of photoelectrochemical water splitting devices. Concentration of elements in the films was determined by RBS and ERD method. FTIR, Raman and I-V measurement were used before and after immersion of samples to aqueous sulfuric acid electrolyte. Differences between Raman or FTIR spectra and differences between I-V characteristics before and after immersion to electrolyte are discussed.

Amorphous silicon carbide in various forms, thin films or bulk structures, is a longer period used in microelectronics, power electronics, sensors and mechanical engineering. Thin films of n-doped amorphous silicon carbide (a-SiC:H) in combination with crystalline silicon representing heterostructure for the solar cells were object of this study. DC and AC measurements and subsequent analyzes were used to estimate the impact of Xe irradiation on electrical properties of studied heterostructure. Impact of Xe irradiation has been quantified by using AC equivalent circuit and the corresponding voltage dependence of AC equivalent circuit elements. The influence of Xe-ions bombardment of a-SiC:H/c-Si heterostructure which resulted in the changes of elements of equivalent circuit — parallel resistance and capacitance — have been identified and explained.

Photovoltaic heterostructures composed of thin film of p-doped amorphous silicon carbide a-SiC and thin films of n-doped crystalline silicon prepared by PECVD deposition technique were the object of this study. Prepared structures have been subjected to accelerated aging process at 85 °C in dry air, respectively under the influence of the different degrees of humidity. The electrical measurements and visual assessments of the samples were performed before the process of accelerated aging and after 25, resp. 90 days. Accelerated aging affects the electrical transport processes in the solar heterostructures. Slight increase in leakage resistance and capacity of the sample was detected in the case of dry heat. The effect of a 100 % humidity resulted in deteriorated performance of the sample. The destruction of the sample was observed in the case of sample immersed in the water. The complex impedance formalism and equivalent circuit were used to estimate the aging influences.

The present paper is devoted to the study of the electron screening effect influence on the rate of d ( d , n ) He 3 reaction in the ultralow deuteron collision energy range in the deuterated metals (ZrD 2 , TiD 2 and TaD 0.5 ). The ZrD 2 , TiD 2 and TaD0.5 targets were fabricated via magnetron sputtering of titanium, zirconium and tantalum in gas (deuterium) environment. The experiments have been carried out using the high-current pulsed Hall plasma accelerator (NSR TPU, Russia). The detection of neutrons with energy of 2.5 MeV from the dd reaction was done with plastic scintillation spectrometers. As a result of the experiments, the energy dependences of the astrophysical S -factor for the dd reaction in the deuteron collision energy range of 2–7 keV and the values of the electron screening potential U e of the interacting deuterons have been measured for the above targets: U e ( ZrD 2 ) = ( 205 ± 35 ) eV ; U e ( TiD 2 ) = ( 125 ± 34 ) eV ; U e ( TaD 0.5 ) = ( 313 ± 58 ) eV . Our results are compared with the other published experimental and calculated data.

The temperature dependence of the enhancement factor for the dd reaction proceeding in TiD2 and ZrD2 is investigated. The experiments were carried out at the Hall pulsed ion accelerator (INP, Polytechnic University, Tomsk, Russia) in the deuteron energy interval 7.0–12.0 keV and at temperatures ranging from 20 to 200°C. The values obtained for the electron screening potentials indicate that the dd reaction enhancement factor does not depend on the target temperature in the range 20–200°C. This result contradicts the conclusions drawn by the LUNA Collaboration from their work.

The paper is devoted to study electron screening effect influence on the rate of d(d, n)3He reaction in the ultralow deuteron collision energy range in the deuterated polyethylene (CD2), frozen heavy water (D2O) and deuterated metals (ZrD2 and TiD2). The ZrD2 and TiD2 targets were fabricated via magnetron sputtering of titanium and zirconium in gas (deuterium) environment. The experiments have been carried out using high-current plasma pulsed accelerator with forming of inverse Z pinch (HCEIRAS, Russia) and pulsed Hall plasma accelerator (NPI at TPU, Russia). The detection of neutrons with energy of 2.5MeV from dd reaction was done with plastic scintillation spectrometers. As a result of the experiments the energy dependences of astrophysical S factor for the dd reaction in the deuteron collision energy range of 2–7 keV and the values of the electron screening potential U e of interacting deuterons have been measured for the indicated above target: U e (CD2) ⩽ 40 eV; U e (D2O) ⩽ 26 eV; U e (ZrD2) = 157 ± 43 eV; U e (TiD2) = 125±34 eV. The value of astrophysical S factor, corresponding to the deuteron collision energy equal to zero, in the experiments with D2O target is found: S b (0) = 58.6 ± 3.6 keV b. The paper compares our results with other available published experimental and calculated data.

Nanocrystalline diamond/amorphous composite carbon films were deposited by plasma enhanced chemical vapour deposition method. The concentrations of species in the films were determined by RBS (Rutherford backscattering spectrometry) and ERD (elastic recoil detection) methods. The RBS results showed the main concentrations of C in the films. The concentration of hydrogen was approximately 20 at. %. Chemical compositions were analyzed by FTIR spectroscopy. IR results showed the presence of C-H specific bonds. Film was used for photocathode application. The original quantum efficiency of prepared photocathode at energy of FH 15,6 mJ was 1,43x10 -6 %.

In this work, we concentrate on the study of the role of ohmic electrode metallization of radiation imaging detectors based on bulk semi-insulating (SI) GaAs. We fabricated SI GaAs radiation detectors with Ti/Pt/Au Schottky contact on one side and In/Au, Mg/Au and Gd/Au contacts on the other side of bulk material with the aim to form hole barrier Schottky contact with non-injecting effect. Current–voltage and noise characteristics and also detection performance of detectors are measured and evaluated. Observed results are discussed and compared with detector using standard AuGeNi non-alloyed ohmic metallization.

Nanocrystalline NiO thin films were deposited by dc reactive magnetron sputtering in a mixture of oxygen and argon and subsequently coated by Au on a NiO film surface. Very thin Au overlayers with a thickness of about 1 and 7 nm have been prepared by magnetron sputtering. Then, the surface modified NiO films have been analysed by TEM, EDX and SEM. NiO thin films showed a polycrystalline structure with the size of nanocrystals ranging from a few nanometers to 10 nm. Electrical responses of NiO-based structure towards hydrogen have been measured.

Nitrogen-doped amorphous silicon carbide films were grown by a plasma enhanced chemical vapour deposition (PE CVD) technique. The actual amount of nitrogen in the SiC films is determined by Rutherford backscattering spectrometry (RBS). For irradiation experiments we use electron beams with a kinetic energy 200 keV, a pulse duration of 300 ns, and a beam current of 150 A/cm2. It is found that with increased nitrogen doping and following activation of dopants the resistivity of the amorphous SiC films is substantially reduced.

Amorphous silicon carbide films were deposited by plasma enhanced chemical vapor deposition (PECVD) technology using SiH 4 , CH 4 , H 2 and NH 3 gas as precursors. The concentration of elements in the films was determined by RBS and ERD analytical method. Chemical compositions were analyzed by FT-IR spectroscopy. Raman spectroscopy study of the SiC films were performed by using a Raman microscope. Irradiation of samples with neutrons to fluencies A(7.9x10 14 cm -2 ), B(5x10 15 cm -2 ) and C(3.4x10 16 cm -2 ) was performed at room temperature. Raman spectroscopy results of SiC films showed decreasing of Raman band feature intensity after neutron irradiation and slightly decreased with increased neutron fluencies. Raman spectra differences between types of films before and after neutron irradiation are discussed. The electrical properties of SiC films were determined by the I-V measurement at 295 K. The measured currents were greater (about two order) after irradiation than the current before irradiation for all samples and rose up with neutron fluencies.

The plasma CVD reactor with parallel plate electrodes was used for plasma enhanced chemical vapor deposition (PECVD) of two type’s silicon carbide thin films on Si substrates. The concentration of elements in the films was determined by RBS and ERD analytical method simultaneously. The chemical compositions of the samples were analyzed by FTIR method. RBS and ERD results showed that the films contain silicon, carbon, hydrogen and small amount of oxygen. FTIR results confirmed the presence of Si-C, Si-H, C-H, and Si-O bonds. From the FTIR spectra the main following vibration frequencies were determined: the band from 2800 to 3000 cm-1 is attributed to stretching vibration of the CHn group in both the sp2 (2880 cm-1) and sp3 (2920 cm-1) configurations. The band at 2100 cm-1 is due to SiHm stretching vibrations. The band at 780 cm-1 can be assigned to Si-C stretching vibration. Main features of FTIR spectra were Gaussian fitted and detailed analyses of chemical bonding in SiC films were performed. Differences between two types of SiC films were discussed with the aim to using these films in the heterojunction solar cell technology.

The heterojunction solar cell structure consists of thin doped amorphous SiC layer and crystalline n-type silicon. Dark and light current-voltage (I–V) measurements were performed in order to obtained basic electric and PV parameters of prepared solar cell structures. Biased complex impedance spectra of Al/a-SiC/c-Si(n)/Al heterojunction in the dark are reported and analyzed. AC equivalent circuit was obtained by fitting of impedance dependences and its electronic components were used to describe the electronic transport properties of prepared structures.

Thin films of p-doped amorphous SiC used as an emitter layer for heterojunction solar cells have been the subject of this work. Thin amorphous SiC films were prepared by PECVD technology. Impact of dopation on the resulting properties of heterojunction was the main object of this study. The DC measurements under dark were performed in order to detect basic electronic properties as a diode ideality factor and saturation current. PV parameters such as fill factor, open circuit voltage and efficiency were obtained from DC measurements under illumination. The impedance spectroscopy analysis was performed by following Cole-Cole principle.

Nanostructured NiO thin films were prepared by dc reactive magnetron sputtering in a mixture of oxygen and argon and subsequently coated by Pt on an NiO film surface. Pt very thin overlayers with a thickness of about 3 and 5 nm have been deposited by magnetron sputtering. The microstructure and surface morphology of the samples have been analysed by XRD and by SEM and AFM, respectively. The electrical responses of the NiO-based sensors towards hydrogen concentration have been also considered. The thickness of the Pt thin layers seems an important parameter in determining the properties of the NiO films as hydrogen sensors.

PECVD silicon carbide films were deposited in a high frequency parallel-plate plasma reactor. The deposition temperatures were 250, 350 and 450 °C respectively. The concentration of species in the SiC films was determined by Rutherford backscattering spectrometry (RBS). Chemical compositions were analyzed by infrared spectroscopy (IR). The IR spectra were measured from 4000 to 400 cm−1. The hydrogen concentration was determined by the elastic recoil detection (ERD) method. Film morphology was assessed by Atomic Force Microscopy (AFM). Our results show that if the deposition temperature increases the value of refractive index is increases. In the case of samples P1 and P2 the concentration of silicon and carbon are 35 and 40 at. % respectively. The concentrations of Si and C in sample P3 are 37 and 40 at. % respectively. The IR spectra revealed the main absorption region between 500 and 1500 cm−1. AFM micrographs of the SiC films prepared by PECVD reveal that the film surface is rather smooth and compact.

Nanocrystalline NiO thin films were prepared by dc reactive magnetron sputtering in a mixture of oxygen and argon and subsequently coated by Pt on an NiO film surface. Very thin Pt overlayers with a thickness of about 3 and 5 nm have been deposited by magnetron sputtering. Then, the modified NiO films have been analyzed by TEM, EELS and AES. NiO thin films showed a polycrystalline structure (fcc NiO phase) with the size of nanocrystals ranging from a few nanometres to 10 nm. TEM observations both of unmodified and Pt-modified NiO films revealed that they were formed by nanocrystals and an amorphous phase. Uniformly distributed Pt particles were produced on top of the NiO surface. According to AES measurements, the presence of Ni in the spectra recorded from Pt pad indicated that the Pt layer has discontinuous nature. Electrical responses of NiO-based sensor structures towards hydrogen have been measured.

The study presents the results of an experimental investigation of the role of sophisticated monolithic linear X ray strip detectors based on semi-insulating (SI) GaAs introducing etched trenches around strips into the technology. The strip line detectors are preferably determined for application in digital X-ray imaging. Investigated strip detectors were created by evaporation of Au/Zn (top) and AuGeNi (bottom) eutectic alloys, respectively onto LEG SI GaAs wafer using lift-off technique. Topology of strip line was modified by trenches using RIE etching around the detector strip. The influence of the trenches on detection properties of strip detectors are investigated in terms of charge collection efficiency, energy resolution and detection efficiency using gamma sources 241 Am and 57 Co. Obtained results show worsening of CCE in the case of trench placed on the bottom - ohmic side of detector, otherwise an improvement of energy resolution after etching treatment was observed. Current-voltage measurements show remarkable decrease of reverse current after etching the trenches.

The present work describes a portable digital X-ray scanner based on bulk undoped semi-insulating (SI) GaAs monolithic strip line detectors. The scanner operates in “quantum” imaging mode (“single photon counting”), with potential improvement of the dynamic range in contrast of the observed X-ray images. The “heart” of the scanner (detection unit) is based on SI GaAs strip line detectors. The measured detection efficiency of the SI GaAs detector reached a value of over 60 % (compared to the theoretical one of ∼75 %) for the detection of 60 keV photons at a reverse bias of 200 V. The read-out electronics consists of 20 modules fabricated using a progressive SMD technology with automatic assembly of electronic devices. Signals from counters included in the digital parts of the modules are collected in a PC via a USB port and evaluated by custom developed software allowing X-ray image reconstruction. The collected data were used for the creation of the first X-ray “quantum” images of various test objects using the imaging software developed.

In this work, basic tasks related to the spectrometric performance of X- and γ-ray radiation-imaging detectors based on semi-insulating (SI) GaAs are studied. The state of the art in this field is reported. The importance of a low-noise front-end read-out electronic chain is demonstrated. Four different charge-sensitive preamplifiers are tested and compared. The investigation of SI GaAs detectors considered for imaging applications is focused on the study of different electrode technologies. A blocking electrode is obtained by a surface Schottky barrier or an MBE-grown P + layer. An ohmic N + contact is fabricated using alloyed AuGeNi metallization or an advanced, quasi-ohmic non-injecting system created by a non-stoichiometric buffer grown by low-temperature MBE at the metal-semiconductor interface. This latter approach is considered as an improvement of the “non-alloyed” ohmic contact. The pulse height spectra obtained with 241 Am and 57 Co sources and corresponding detector energy resolution are evaluated. The role of detector geometry and temperature on the spectrometric performance is studied.

We present properties of nitrogen-doped amorphous silicon carbide films that were grown by a plasma enhanced chemical vapour deposition (PECVD) technique and annealed by pulsed electron beam. Samples with different amounts of N were achieved by a small addition of ammonia NH3 into the gas mixture of silane SiH4 and methane CH4, which were directly introduced into the reaction chamber. The actual amount of nitrogen in the SiC films was determined by Rutherford backscattering spectrometry (RBS). A simulation of the RBS spectra was used to calculate the concentration of carbon, silicon and nitrogen.

We present the pulsed de magnetron sputtering method in which a nickel target is sputtered in a mixture of argon and reactive oxygen gas. The flow modulation of oxygen is proposed to enhance the deposition process in the preparation of the oxide films. The flow rate of oxygen is modulated periodically in time and during deposition when oxygen flows is cut off to remove the oxide formed on the target. A modulated deposition process was monitored directly by optical emission spectroscopy, measuring the deposition rate and the partial pressure. The effect of the different oxygen flow, which was changed periodically, changes with time on the target potential and the deposition rate were investigated. The variations of the Ni/O atomic ratios in NiO films were revealed by SIMS method.