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The diffusion profiles of the concentration of electrically active and total concentrations of the magnesium impurity in silicon are measured. Diffusion is carried out by the sandwich method into FZ dislocation-free n-type silicon at the temperatures Tdiff = 1000 and 1100°C, and at a process duration from 0.5 to 22.5 h. The concentration profiles $${{N}_{{{\text{M}}{{{\text{g}}}_{i}}}}}$$(x) of the electrically active magnesium component are determined by the differential-conductivity method, and the total-concentration profiles Ntotal(x), by secondary-ion mass spectroscopy. It is established that the total concentration of magnesium in the samples is ~2 orders of magnitude higher than that of the electrically active component. It is also found that the diffusion coefficient $${{D}_{{{\text{M}}{{{\text{g}}}_{i}}}}}$$ of interstitial magnesium depends on the diffusion time and decreases with an increase in the duration of the process. Assumptions are made about the physical processes, which can lead to the formation of an electrically inactive component of magnesium impurity and to the dependence of the effective diffusion coefficient on time.

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Infrared absorption cross sections and corresponding oscillator strengths of several intracenter transitions of double donors in silicon, interstitial magnesium (Mg; group IIA) and substitutional chalcogens (Ch = S; Se; group VI), were determined for impurity densities in the ranges \ud1\ud×\ud10\ud14\ud–\ud1.6\ud×\ud10\ud15\udatoms\ud/\udc\udm\ud3\ud for Mg and \ud2\ud×\ud10\ud13\ud–\ud2\ud×\ud10\ud16\udatoms\ud/\udc\udm\ud3\ud for chalcogens. The concentrations of electrically active atomic and diatomic donor centers were derived from the Hall effect measurements. The experimental integrated cross sections were obtained from low-temperature impurity absorption spectra. The oscillator strengths of related donor transitions were derived and compared with those for shallow single donors in silicon, both determined experimentally and predicted theoretically. The transitions of oscillator strengths of double donors follow the decreasing trend with decreasing radius of donor ground states and increasing an impurity binding energy.

Electrically active centers in n-type magnesium-doped silicon crystals are studied by deep-level transient spectroscopy (DLTS). Magnesium is introduced by diffusion from a metal film on the surface at 1100°C. It is found that two levels with a similar concentration of ~6 × 1014 cm–3 dominate in the DLTS spectrum; the value approximately corresponds to the interstitial magnesium (Mgi) concentration expected from diffusion conditions and published data on the Hall effect. The dependence of the electron emission rate from these levels on the electric-field strength agrees qualitatively with the Poole–Frenkel effect, which indicates the donor nature of both levels, although the absolute value of the effect differs from theoretical value. The activation energies of these levels found by the extrapolation of emission rates measured at various temperatures to zero field are 112 and 252 meV, which coincides within the accuracy with energies of ground states of the first and second donor levels of Mg determined previously from optical absorption. Thus, it is shown that when using high-quality initial material and the selected diffusion mode, interstitial magnesium atoms are the dominant centers with levels in the upper half of the band gap.

Magnesium (Mg) atoms in interstitial positions of a silicon host lattice form double donor centers. The binding energy of the neutral $\mathrm{M}{\mathrm{g}}^{0}$ state corresponds to midinfrared wavelengths. Due to its interstitial character, the outer orbitals of Mg atoms can form specific bonds with different trace elements in the silicon crystal. These occur as single and double donors that become detectable by infrared spectroscopy when the concentration of either Mg or the dopant coupled to it is sufficiently large. Infrared absorption spectroscopy at high magnetic fields allows us to observe the Zeeman effect of several shallow Mg-related donor complexes and neutral Mg donors, very similar to those observed for hydrogenlike centers. The quadratic Zeeman effect indicates a hydrogenlike center structure of the excited states and spatial localization of complexes with a single excess electron in its outer shell, which are formed by Mg with an impurity atom. In contrast, Mg complexes formed by bonds with two electrons are closer to substitutional double donors in silicon.

Diatomic centers of double donor doped silicon have lower chemical shifts as compared to the corresponding atomic impurity and by this essentially extend spectral sensitivity of silicon extrinsic infrared detectors towards longer wavelengths. Additional expansion of the detector spectral band, up to the effective-mass approximated theoretical value of about 2.7 THz, can be obtained by photothermal infrared absorption originated from intracenter transitions of a dopant. Due to large energy gaps between lowest excited states of double donors in silicon related photothermal transitions have not been considered yet as applicable for photoconductive light detection. We have investigated the operational conditions suitable for expanding the low temperature detection wavelength cut-off of selenium doped silicon infrared detectors towards 6.2 μm.

Magnesium in silicon primarily occupies an interstitial site, where it acts as a moderately deep double donor. It has recently been shown that interstitial magnesium can pair with the substitutional acceptor boron to form a shallow single-donor center. In this work, we demonstrate analogous complexing with the other group-III acceptors Ga, In, and Al. We observe the odd-parity excited states of each shallow donor complex in absorption spectra, from which the ionization energies are obtained. These complexes can localize excitons, and we observe the donor bound exciton transitions of all four centers in photoluminescence spectra. The Mg-acceptor complexes are found to obey Haynes rule, which predicts a linear relationship between donor ionization energy and donor bound exciton localization energy.

The optical properties of magnesium impurity in silicon, whose atoms at interstitial positions in the lattice are deep double donors with an ionization energy of 107.56 meV in the neutral state, were studied. For optical transitions from the ground state of a neutral center to the excited levels 2p0 and 2p, the absorption cross sections and oscillator strengths were determined. These parameters were calculated from the impurity absorption spectra that were measured at T  K in samples with different magnesium concentrations. The deep donor content in the samples was determined using Hall effect measurements in the temperature range 78–300 K. The obtained characteristics of intracenter transitions in magnesium were compared with the corresponding literature data for shallow Group V donors in silicon, which are substitutional impurities. It was found that the optical characteristics of the investigated transitions in magnesium are consistent with the dependences of the corresponding parameters on the ionization energy for shallow donors, extrapolated to the region of larger electron binding energies.

The diffusion doping of dislocation-free single-crystal silicon with magnesium is studied in the temperature range 1000–1200°C. The conventional sandwich method is used as the doping method. It is found that the diffusion coefficient of magnesium is described by a universal Arrhenius curve in the extended temperature range 600–1200°C, with data earlier obtained for the range 600–800°C taken into consideration. The relatively low activation energy of diffusion transport (1.83 eV) is indicative of the interstitial mechanism of impurity diffusion.

The results of experiments aimed at the observation of split 1s states in Mg-doped Si are reported. From the results, it is possible to determine the chemical shift and exchange interaction energy of a neutral Mg donor in Si. The position of the 1s(E), 1s(T2), and 2s(A1) parastates determines the possibility for attaining population inversion and the specific mechanism of stimulated Raman scattering. The energy of the 1s(T2) parastate is determined from the position of the Fano resonances in the photoconductivity spectrum of Si:Mg at T = 4 K, and the energies of the 1s(T2) and 1s(E) orthostates from the transmittance spectra at elevated temperatures. On the basis of the experimental data, the relaxation rates are estimated, and the possible mechanisms of stimulated emission are analyzed.

We use the greatly improved optical linewidths provided by highly enriched $^{28}$Si to study a photoluminescence line near 1017 meV previously observed in the luminescence spectrum of natural Si diffused with Mg, and suggested to result from the recombination of an isoelectronic bound exciton localized at a Mg-pair center. In $^{28}$Si this no-phonon line is found to be comprised of five components whose relative intensities closely match the relative abundances of Mg-pairs formed by random combinations of the three stable isotopes of Mg, thus confirming the Mg-pair hypothesis. We further present the results of temperature dependence studies of this center that reveal unusual and as yet unexplained behaviour., 5 pages, 4 figures

We have performed high field magnetoabsorption spectroscopy on silicon doped with a variety of single and double donor species. The magnetic field provides access to an experimental magnetic length, and the quadratic Zeeman effect, in particular, may be used to extract the wave-function radius without reliance on previously determined effective mass parameters. We were, therefore, able to determine the limits of validity for the standard one-band anisotropic effective mass model. We also provide improved parameters and use them for an independent check on the accuracy of effective mass theory. Finally, we show that the optically accessible excited-state wave functions have the attractive property that interactions with neighbors are far more forgiving of position errors than (say) the ground state.

The deep double donor levels of substitutional chalcogen impurities in silicon have unique optical properties which may enable a spin/photonic quantum technology. The interstitial magnesium impurity (Mg$_i$) in silicon is also a deep double donor but has not yet been studied in the same detail as have the chalcogens. In this study we look at the neutral and singly ionized Mg$_i$ absorption spectra in natural silicon and isotopically enriched 28-silicon in more detail. The 1s(A$_1$) to 1s(T$_2$) transitions, which are very strong for the chalcogens and are central to the proposed spin/photonic quantum technology, could not be detected. We observe the presence of another double donor (Mg$_{i*}$) that may result from Mg$_i$ in a reduced symmetry configuration, most likely due to complexing with another impurity. The neutral species of Mg$_{i*}$ reveal unusual low lying ground state levels detected through temperature dependence studies. We also observe a shallow donor which we identify as a magnesium-boron pair.

The decomposition of a solid solution of interstitial magnesium Mgi in silicon is studied. Float-Zone dislocation-free single-crystal n-Si with a resistivity of ~8 × 103 Ω cm and oxygen and carbon contents of ~5 × 1014 cm–3 and ~1 × 1015 cm–3 is used in the experiments. The samples are doped using the diffusion sandwich method at T =1100°C followed by quenching. Decomposition of the supersaturated Mgi solid solution is studied by observing the kinetics of increasing the resistivity of doped samples resulting from their annealing in the range T= 400–620°C. It is found that the decomposition is characterized by an activation energy of Ea ≈ 1.6 eV, which is close to the previously determined diffusion activation energy of Mgi in silicon. It is also shown that Si:Mg exhibits stable properties at temperatures not exceeding 400°C, which is important for its possible practical application.

The characteristic time ϑ of the response of the Townsend discharge in argon is determined in short gaps at room and cryogenic (∼100 K) temperatures. In the structure used in experiments, one electrode is made of semi-insulating gallium arsenide, which ensures stabilization of the spatially homogeneous state of the discharge. The values of ϑ are obtained from the observed resonance frequency of the given structure. It is found that for both experimental temperatures, time ϑ in argon considerably exceeds the experimental values for a discharge in nitrogen in thin gaps, which were obtained earlier at room temperature. The results are of interest, in particular, for the development of high-speed IR image converters, in which the Townsend discharge in thin gaps is used.

The diffusion of magnesium impurity in the temperature range T = 600–800°C in dislocation-free single-crystal silicon wafers of p-type conductivity is studied. The surface layer of the wafer doped with magnesium by the ion implantation technique serves as the diffusion source. Implantation is carried out at an ion energy of 150 keV at doses of 5 × 1014 and 2 × 1015 cm–2. The diffusion coefficient of interstitial magnesium donor centers (Di) is determined by measuring the depth of the p–n junction, which is formed in the sample due to annealing during the time t at a given T. As a result of the study, the dependence Di(T) is found for the first time. The data show that the diffusion process occurs mainly by the interstitial mechanism.

Noise in a low-current Townsend discharge in argon and nitrogen is studied. Experiments were performed in a ``semiconductor--gas-discharge'' structure constituted by a short plane-parallel discharge gap and a high-resistivity photosensitive semiconductor electrode. The noise of optical emission from gas excited by the discharge was investigated with a photomultiplier. Experiments were done at the room temperature of the discharge structure. According to the obtained data, the noise of discharge glow in Ar is astonishingly low---similar to that earlier found for the cryogenic discharge in this gas. At equal time-average photon fluxes emitted by discharges in both gases, the noise of gas glow in nitrogen substantially exceeds the corresponding value for argon. A statistical processing of signals of glow brightness for the two gases revealed the origin of this difference: While the power spectral density of noise in nitrogen is specified by a band of frequencies with the increased density, in argon it is nearly constant in an extended frequency range. At the same time, intensity of noise is practically the same for both gases in the ranges of low and high frequencies. The relationship of the increased noise in nitrogen with a low critical current density for oscillatory instability of the Townsend discharge in this gas is considered.

Selenium-doped silicon single crystals are studied for the case of an impurity introduced by diffusion from the gas phase. Doping is performed in sealed quartz ampules at a temperature of 1240°C over the course of 240 h. The dependence of the concentration of the introduced deep donor centers of various types on the diffusant vapor pressure pSe is examined. It is found that samples with a concentration of atomic Se centers exceeding 1015 cm−3 can be obtained at comparatively low pSe (0.02–0.06 atm). In this case, the content of diatomic Se2 complexes is lower by an order of magnitude and more. The results obtained may be of interest for those who study nonlinear optical phenomena involving deep donor centers in silicon.

The paper describes a study of the electron energy distribution function in the self-sustained direct current (dc) Townsend discharge. A three-electrode microdischarge structure with a plane-parallel arrangement of electrodes is applied in the experiments. The device comprises two discharge gaps of a small width having a common electrode in the form of a fine-grained metal mesh. A high-resistivity cathode to the first gap is applied, which ensures the spatial uniformity of the Townsend discharge in the gap. The second gap serves as a retarding field analyzer of energy of electrons that are generated in the region of the Townsend discharge and pass through cells in the grid electrode. Experiments are carried out for discharges in argon and nitrogen near the minimum of the Paschen curve. According to the data obtained, shapes of the distribution function for the investigated gases are different: for Ar, a local maximum at energies of 1–3 eV is observed in the distributions, in contrast to N 2. At the same time, the effective electron temperature—determined from the high-energy tail of a distribution—is close for both gases and lies in the range of 0.8–1.9 eV. This is significantly lower than electron energies that give numerical calculations for E / N values corresponding to the conditions of experiments. Among the possible reasons for the difference is the fundamental property of a dc Townsend discharge: electrons in the subanode layer—where they are accumulated and from where they pass to the analyzer—gain energy mainly on a relatively small ionization length in the gas.

An anodic oxidation of GaAs substrates in a non-self-sustained low-current dc Townsend discharge is investigated. The process is carried out at the room temperature in a three-electrode microreactor filled by 98%Ar + 2%O2 gas mixture. Investigation of the oxidation kinetics indicates that the formed oxide is characterized by a high resistivity, ρ ∼ 1011 Ω·cm. It is demonstrated the application of the method for formation of oxide films with dimensions of tens of microns, which thickness is on the nanometer scale. Examination of the “GaAs substrate - oxide layer” interface using the high resolution transmission electron microscopy has revealed that the oxide is characterized by the amorphous structure.

The effect of the high-temperature heating (at 1340°C) of sulfur-doped silicon samples and their subsequent quenching is studied. The results of such a treatment are analyzed on the basis of Hall-effect data obtained in the temperature range T = 78–500 K. It is shown that the heating duration strongly affects the relative concentrations of different types of deep sulfur-related centers. At comparatively short heating durations of t = 2–10 min, the concentration of quasi-molecular S2 centers and S X complexes substantially decreases, whereas the density of monoatomic S1 centers grows. At the same time, the heating of a sample is accompanied by a monotonic decrease in the total concentration of electrically active sulfur over time. The results obtained make it possible to give recommendations concerning the optimal conditions for the fabrication of samples with a high concentration of S1 centers. The absorption spectra of the samples show that the method is promising for the observation of a number of quantum-optical effects involving deep S1 donors in silicon.

We have manufactured mid-infrared chalcogen donor centres in silicon by high-temperature diffusion doping. Electrical characterisation has shown that we can control the ratio of different donor centre concentrations. FT-IR spectroscopy reveals very narrow lines in the mid-infrared spectral band. We have now performed the first time-domain measurements on the donor centre excited states. Our preliminary results suggest excited state lifetimes with nanosecond timescales.

Low-current Townsend discharge in nitrogen has been studied in the temperature range of T = 100–300 K in a semiconductor-gas-discharge structure. It was found that the sustaining voltage US increases with time when a current is passed through the structure at low T. This effect was not observed at room temperature. A hypothesis is put forward that a film of a neutral phase of nitrogen is formed on the electrodes under cryogenic discharge conditions. The presence of the condensed thin-film phase leads to a decrease in the secondary electron emission from the electrode and to a corresponding increase in US. A possible mechanism of the phenomenon is associated with the formation of large neutral aggregates in the form of [N+2(N2)n]– in the gas discharge volume. The condensation of these aggregates seems to yield a phase that is comparatively stable at cryogenic temperatures (© 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)

The results of experimental investigation of the stability boundary for a spatially homogeneous state of a discharge in the planar gap of a “semiconductor-gas-discharge” cryogenic system filled with nitrogen are considered. The semiconductor cathode was prepared from single-crystalline silicon doped with a deep-lying impurity. Quantitative data are obtained for the conditions of formation of a hexagonal dissipative structure in the current distribution for two values of the discharge gap length upon a change in the gas pressure and in the conductivity of the cathode. It is found that for a fixed gap length, the formation of the critical state can be described approximately by a universal function of the electrode conductivity and gas pressure.

The study is concerned with the effect of short-term high-temperature heating on Si:Se and Si:S samples, whose surface layers are doped with phosphorus to high concentrations. It is found that the resistivity of the wafers substantially increases deep in the bulk within up to ∼10 μm. The experimental data suggest that this effect is due to enhanced diffusion of chalcogen in the presence of the phosphorus-doped surface region. The mechanism of the effect is the injection of nonequilibrium interstitial silicon atoms from the layer heavily doped with phosphorus to the bulk of the sample. This results in a shift of the equilibrium between the concentrations of substitutional and interstitial impurity atoms towards higher concentrations of interstitials and, as a consequence, towards the increase in the relative content of the fast-diffusing interstitial component of the impurity.

Planar extrinsic sulfur-doped silicon detectors for infrared (IR) semiconductor-discharge gap image converters intended for use in high-speed thermography of remote objects have been developed. The detectors were fabricated by high-temperature diffusion of sulfur into silicon wafers from the vapor phase. The dependence of doping efficiency on the sulfur vapor pressure in the course of diffusion was analyzed. The detector fabrication technology was optimized to meet the specific requirements for their operation in the microdischarge devices considered. The detectors were tested in a laboratory setup comprising a blackbody source of IR light, an image converter, and a pulsed CCD camera for recording the converted images. The converter equipped with the detector can provide imaging of objects heated to a temperature, T min ≈ 200 °C, with a temporal resolution on the order of 10 −6 s and spatial resolution of about 5 lines/mm.

High-speed recording of processes in the IR spectral range can be carried out using image converters of the “semiconductor photodetector + gas discharge gap” type. To develop photodetectors with the properties required for this purpose, the effect of the selenium vapor pressure P Se on the doping efficiency of single-crystal silicon with selenium has been studied. Selenium was introduced by diffusion in sealed quartz cells at a temperature of 1240°C in the pressure range P Se = 0.27–1.0 atm. Doped samples were studied by performing temperature measurements of the Hall effect. A heavy dependence of the concentration of the impurity centers introduced on P Se was observed. It was found that the doping effect is the same for starting crystals produced by floating zone melting and by the Czochralski method. The data obtained were used to fabricate photodetectors that can be employed in high-speed thermography with the use of the image converters under consideration.

Subnanosecond dynamics of optically excited electrons bound to excited states of neutral magnesium donor centers in silicon has been investigated. Lifetimes of nonequilibrium electrons have been derived from the decay of the differential transmission at photon energies matching the intracenter and the impurity–to–conduction band transitions. In contrast to hydrogen-like shallow donors in silicon, significantly longer lifetimes have been observed. This indicates weaker two-phonon and off-resonant interactions dominate the relaxation processes in contrast to the single-intervalley-phonon assisted impurity-phonon interactions in the case of shallow donors in silicon.

Fast photonic switches, in which light controls light, can be created based on high-voltage GaAs nanostructures with a thin (nanodimensional) surface dielectric layer. The switches offer a high operation speed that ensures optical data recording and transmission at a rate of 104-105 cps, possess a large modulation amplitude, and can operate at a relatively low optical control signal power (I

The work aims at approaching the solution of the problem of developing sensitive silicon detectors for high speed IR imaging devices which are semiconductor – gas discharge systems. Among the requirements to detectors is their operation at the temperature which is somewhat higher than that of liquid nitrogen. To meet this requirement, a set of deep impurities is analyzed. It is emphasized that silicon doped with sulphur is a good choice to reach the aim. The doping of silicon with sulphur is done by the technique of high temperature diffusion. Data of the Hall measurements indicate the presence of large density of shallow donor levels in the material obtained. To compensate them, acceptors are introduced afterwards with using radiation doping techniques. Testing of the fabricated detectors in the converter setup shows that they provide imaging of IR fields of temperature T ~ 270 0C with the temporal resolution in the order of 3 µs.

Doping of silicon with magnesiumis investigated by a sandwich diffusion technique. Temperature dependence of the diffusion coefficient in the dislocation-free silicon in the range of 1000–1200 8C is determined. It obeys the Arrhenius behavior over the range of 600–1200°C, when the data obtained earlier for the lower temperatures are taken into consideration. Preliminary results on Mg diffusion in the dislocated crystals are also presented. The dislocation-free Si:Mg samples are investigated with the Hall-effect measurements and the low-temperature Fourier spectroscopy. A decrease in concentration of Mg interstitials (about 15%) has been observed after 31 months of the samples storage at room temperature, when a commercially available FZ silicon was used as a starting material. The effect of the samples degradation is proposed to be due to a formation of Mg-O complexes. When using a special silicon purified from oxygen and carbon with concentrations below or equal to 1.5 x 10^14 and 5 x 10^14 cm ^-3, respectively, a decrease in the density of interstitial magnesium has not been noticed during this period. The storage of Si:Mg samples prepared from pure silicon gives rise to the formation of an unknown center, whose ionization energy is between the corresponding values for the interstitial Mg^0 centers and (Mg-O)^0 complexes.

It is established that the cooling of argon-or nitrogen-filled microdischarge devices to cryogenic temperatures significantly affects the threshold potential of discharge initiation. For a discharge in the nitrogenfilled gap with a brass cathode, this effect can be explained by a decrease in the secondary electron emission coefficient, while the influence of cooling on the argon-filled gap has a more complicated nature. The results are of importance for the development of cryogenic microdischarge devices.

The formation kinetics of the S2 complex in sulfur-doped silicon is studied. It is shown that the processes in which chalcogen “quasi-molecules” are formed in Si:S and Si:Se are similar. The difference is in the binding energy in a “quasi-molecule”: it is 1.5 times lower for S2, compared with the Se2 complex.

Just as phosphorus in silicon produces a hydrogenic defect, the double donor selenium in silicon is an analog of helium. We have measured the impurity absorption spectrum at high magnetic field, and we show that the odd-parity excited states of Si:Se behave identically to those of Si:P. This fact allows us to isolate the electron-electron interactions (exchange and correlation) in the ground state from the quadratic Zeeman effect. The field tuning allows us to put upper limits on the strength of some of these interactions (e.g., at 30 T the electron-electron correlation interaction in the ground state of Se is less than about 40 \ensuremath{\mu}eV; at 30 T the quadratic Zeeman energy in the ground state of P is less than about 200 \ensuremath{\mu}eV).

This paper investigates the dynamics of the Townsend discharge in nitrogen in narrow gaps. To provide stability of discharge in a broad range of current, we apply a plane-parallel structure, one of the electrodes of which is made of a high-resistivity gallium arsenide. The results of experiments are analyzed in the framework of theory [Yu. P. Raizer et al., Tech. Phys. 51, 185 (2006)], which considers the dynamics of discharge in short nitrogen-filled gaps of similar structures. According to the theory, a key parameter of discharge dynamics is time $\ensuremath{\vartheta}$ that defines the rate of discharge response to perturbations. In our work, time $\ensuremath{\vartheta}$ is experimentally found by analyzing the noise spectrum of the discharge glow in the stable and spatially uniform state of the structure. This characteristic time depends linearly on the discharge gap width, which corroborates conclusions based on the standard model of Townsend discharge. However, its values are substantially shorter compared to those predicted by theory. The relationship between $\ensuremath{\vartheta}$ and experimentally observed critical current density for the oscillatory instability, ${j}_{\text{cr}}$, is applied to find the discharge negative differential resistance for a set of parameters of the discharge gap.

The temperature dependence of the properties of the low-current Townsend discharge in nitrogen is studied. The experiments are carried out on a device with a high-resistivity semiconductor electrode in the temperature range 85–292 K at a current density not exceeding 25 μA cm−2. The discharge gap of the device is 0.85 mm, while the nitrogen density corresponds to the gas pressure Pa (49.5 Torr) at T = 292 K. The earlier increase found in the discharge sustaining voltage in time at a fixed current is quantitatively investigated for the cryogenic discharge. The relaxation is accompanied by transitions to new discharge states with an increased noise intensity. The characteristic time of the relaxation is hundreds of seconds. The effect is especially pronounced in the range of 100–150 K and is relatively weak at room temperature. The interpretation of the experimental data is based on the hypothesis that considers the formation of neutral aggregates of nitrogen in the form [(N2) n ]− in the discharge volume. The condensation of the clusters on the cathode leads to a change in its emission properties, which changes the properties of the discharge.

We consider the possibility of creating a semiconductor device converting continuous laser radiation into a sequence of pulses in the visible and infrared wavelength range.

The influence of stationary spatially homogeneous Townsend discharge on the (1 0 0) surface of semi-insulating GaAs samples is studied. Samples exposed to both electrons and ions in a nitrogen discharge at a current density j = 60 µ Ac m −2 are studied by means of x-ray photoelectron spectroscopy, ellipsometry and atomic force microscopy. It is shown that an exposure to low-energy ions (

The size and location of the area of gas breakdown at the surface of an M(GD)SM structure based on a bismuth silicate crystal was studied under uniform illumination conditions. The amount of energy absorbed in the crystal that leads to breakdown of the gas layer is determined.

Wide gap, insulating semiconductor crystals offer great promise in photoelectric devices, especially as detectors of electromagnetic and nuclear radiation, but are not widely used because they become polarized during operation. During operation of detectors using these crystals with a high concentration of deep impurity levels, electrical charges build up and produce a change, over time, in the electric field within the crystal and in the magnitude of the detector photoresponse. Since it is impossible to avoid impurity centers in these crystals at this time, we propose new approaches to creating radiation detectors-dosimeters which do not become polarized over time, but rely on productive use of the polarization charges that accumulate in them.

A new type of semiconducting dosimeter is proposed for real-time monitoring of nuclear radiation energy (dose). This dosimeter produces an electrical output signal directly proportional to the incident radiation dose (and not its intensity) and its sensitivity to this radiation dose can be controlled.

Photon switches of a new type, based on semiconductor nanostructures have been developed. It reveals universal pure optical switches. Application of these switches lies in a field of systems of optical processing of information, optical calculating devices, totally optical communication lines with optical addressing of informational signals etc . The switches display high switching frequency (up to 106 cycL/sec), large modulation amplitude, function under weak controlling optical signal with power densities I

This article describes and studies a new type of device for quantitative measurements of radiation energy.

The paper concerns the development of a new type of semiconductor detectors based on wide-gap insulating crystals, which are not polarized during the registration of intensive nuclear radiation, x-ray or electromagnetic waves. The detectors offered allow simultaneous registration of the shape and intensity and energy (doze) of radiation as well. I.e. they are detectors-dozemeters of radiations, reveals linear lux-ampere characteristics in a wide range of radiation intensities, are highly sensitive and stable under radiation. Detectors could be prepared on the basis of various insulating crystals with a gap width 2 - 6 eV.