New type of photoelectric converter based on an n-CdO/a-C/p-Si heterostructure

A new system for a photoelectric converter is proposed, and its photoelectric properties are studied, using an n-CdO/a-C/p-Si heterostructure as an example. The distinguishing feature of the structure is that the broad-band insulating layer of SiO₂ on the surface of the silicon is replaced by a narrow-band layer of amorphous carbon, while a layer of CdO is used as the upper electrode. It is shown that an increase of the short-circuit current because of impact ionization can be expected in such a heterostructure. The results of the paper show that it is worthwhile to use CdO films in practice as transparent electrodes. Pis’ma Zh. Tekh. Fiz. 23, 1–6 (November 12, 1997)     

Influence of local pressure on the current-voltage characteristic of Au-Si〈Ni〉-Sb structures

Results of an investigation of the influence of local pressure on the current-voltage characteristic of Au-Si〈Ni〉-Sb structures are presented for the first time. It is shown that nickel impurities in the silicon increase the total strain sensitivity n-Si〈Ni〉 structures. Pis’ma Zh. Tekh. Fiz. 23, 62–64 (May 12, 1997)     

Suppression of large-scale structures in a gas-saturated impact jet

The suppression of large-scale vortex formations under gas-saturation conditions is detected on the basis of measurements of the pulsation component of the surface friction when an axisymmetric hot jet of a fluid impinges on an obstacle. The conditions for the resonant enhancement of coherent structures and the suppression of broad-band turbulence are determined for single-phase and gas-saturated impact jets. The evolution of various pulsation components in the gradient region of an impact jet is analyzed. Pis’ma Zh. Tekh. Fiz. 25, 82–88 (May 12, 1999)     

Phase optical bistability in structures with surface plasmons

A theoretical analysis is made of the phenomenon of phase optical bistability in structures with surface plasmons. It is shown that in an optical waveguide with a nonlinear layer, not only amplitude but also phase bistability may occur when p-polarized radiation is reflected from the nonlinear waveguide. Pis’ma Zh. Tekh. Fiz. 24, 60–65 (August 26, 1998)     

Functional properties of silicon/non-native-oxide heterostructures

It is shown possible to use Al/SnO₂/Si and Al/WO₃/Si metal-oxide-semiconductor structures as photodiodes with a large-area heterojunction. For structures with a film of amorphous tungsten trioxide (a-WO₃) they show promise for applications associated with the development of varicaps and photovaricaps and also chemical sensors of the capacitance type. Pis’ma Zh. Tekh. Fiz. 23, 7–13 (June 26, 1997)     

Deep diffusion doping of macroporous silicon

An investigation is made of the diffusion of boron and phosphorus impurities in macroporous silicon with a regular structure of deep cylindrical pores, for which through doping of the walls was achieved. The ∼150 μm layers obtained were quasiuniformly doped and had a planar diffusion front, and their electric parameters were very similar to those of the doped single crystal. It is demonstrated that deep diffusion of phosphorus may be used to fabricate n-n ⁺ structures. Pis’ma Zh. Tekh. Fiz. 25, 72–79 (December 12, 1999)     

Time modulation of the input signal during recording of holograms on hydrogenated amorphous silicon-liquid crystal structures

It is shown that the resolution and diffraction efficiency of p-i-na-Si:H-liquid crystal structures can be improved without causing any deterioration in the other parameters, by introducing amplitude modulation of the recording light beam synchronous with the supply voltage. Pis’ma Zh. Tekh. Fiz. 23, 20–25 (April 26, 1997)     

Formation of macroparticle structures in an rf induction discharge plasma

It was demonstrated experimentally that macroparticles may undergo levitation and form ordered structures in an rf induction discharge plasma. The experiments were carried out using 1.87 μm melamine formaldehyde particles in neon at a pressure of 25–500 Pa. The generator frequency was 100 MHz. Pis’ma Zh. Tekh. Fiz. 24, 62–68 (October 12, 1998)     

n(p)-InP-n-In2O3-P2O5-Pd diode structures as potential sensors for near-infrared radiation, moisture, and hydrogen

Diode structures based on n(p)-InP with intermediate n-In₂O₃ and P₂O₅ layers were fabricated by electrochemical deposition of Pd. It is shown that when exposed to pulses of water vapor the photo-emf of the structures varies by 60–400% and in the presence of H₂ it can vary by 1.5–2 orders of magnitude. These n(p)-InP-n-In₂O₃-P₂O₅-Pd structures are potential sensors for near-infrared radiation, moisture, and hydrogen. Pis’ma Zh. Tekh. Fiz. 25, 72–78 (December 26, 1999)     

Long-wavelength uncooled sources of λ=5–6 μ radiation using graded-index InAsSb(P) layers grown by liquid-phase epitaxy

Graded-index p-n InAsSb/InAsSbP/InAs structures capable of emitting at the maximum of the spectral curve up to 5.4 μm with a half-width of ∼26 meV (∼0.6 μm) without cooling have been fabricated and studied. This is the longest-wavelength radiation obtained at room temperature in III–V structures grown by liquid-phase epitaxy and the band is the narrowest obtained for semiconductor spontaneous radiation sources. Pis’ma Zh. Tekh. Fiz. 24, 88–94 (March 26, 1998)     

Electroluminescence of quantum-well structures on type-II InAs/GaSb heterojunctions

The electroluminescent properties of quantum-well diode structures on staggered type-II heterojunctions in the InAs/GaSb system, obtained by molecular-beam epitaxy on InAs substrates, are investigated. Electroluminescence is observed in the spectral range 3–4 μm at T=77 K. It is found that emission bands due to recombination transitions involving electrons from the size-quantization levels of both the self-matched quantum wells at the InAs/GaSb type-II heterojunction and of the square quantum wells in short-period superlattices. Pis’ma Zh. Tekh. Fiz. 24, 50–56 (June 26, 1998)     

Deep surface states on the interface between SiC and its native thermal oxide

Deep surface states are discovered on the interface between 6H-SiC and its native thermal oxide by analyzing the C-V characteristics of metal-oxide-semiconductor structures measured at a high temperature (600 K). The maximum of the density of states distributed according to energy (D _tm=2×10¹² cm⁻²· eV⁻¹) is at an energy about 1.2 eV below the bottom of the conduction band of SiC. It is postulated that the states discovered are similar in nature to the P _b centers observed in the SiO₂/Si system. Pis’ma Zh. Tekh. Fiz. 23, 55–60 (October 26, 1997)     

Behavior of epitaxial GaAs layers as α particle detectors

The properties of epitaxial GaAs-based p ⁺-n structures used as light-ion (α particle) were studied. A comparison is made with the latest published data on the possibilities of present-day semi-insulating GaAs (SI-GaAs). It is noted that the content of impurities and structural defects forming deep levels in the band gap of the material is two orders of magnitude lower in epitaxial layers. The deep levels determine the conditions of transport of nonequilibrium carriers in the detector, allowing for trapping of the carriers, and they also determine the electric-field profile. The charge-carrier lifetime was found to be ≥ 200 ns. This is two orders of magnitude longer than the values for SI-GaAs, in complete agreement with the lower content of deep centers. It is shown how deep centers influence the field profile, forming a quite large region of low field values. Pis’ma Zh. Tekh. Fiz. 24, 8–15 (April 12, 1998)     

Hysteresis of the current-voltage characteristics of porous-silicon light-emitting structures

A new hysteresis effect is described in metal-porous-silicon-p-type silicon structures and a new model is proposed to describe current flow in these structures. Pis’ma Zh. Tekh. Fiz. 23, 59–65 (June 12, 1997)     

The possibility of improving the structural perfection of the new heterojunctions GaAs-(Ge2)1− x (ZnSe)x, Ge-(Ge2)1−x (ZnSe)x, GaP-(Ge2)1−x (ZnSe)x, and Si-(Ge2)1−x (ZnSe)x

Based on morphological investigations, as well as on a study of the scanning patterns and diffraction spectra of the heterostructures GaAs-(Ge₂)_1−x (ZnSe)_x, Ge-(Ge₂)_1−x (ZnSe)_x, GaP-(Ge₂)_1−x (ZnSe)_x, and Si-(Ge₂)_1−x (ZnSe)_x, it is shown that the crystal perfection of these structures depends on the choice of the conditions of liquid-phase epitaxy. It is shown that mirror-smooth epitaxial layers of (Ge ₂)_1−x (ZnSe)_x with the lowest stress levels can be obtained on GaAs (100) and Ge (111) substrates. Pis’ma Zh. Tekh. Fiz. 24, 12–16 (January 26, 1998)     

Dielectric properties of planar structures based on ferroelectric Ba0.5Sr0.5TiO3 films

An experimental investigation has been made of the dielectric properties of planar Cu-Cr/Ba_0.5Sr_0.5TiO₃ and YBa₂Cu₃O_7−δ /Ba_0.5Sr_0.5TiO₃ structures in the temperature range 78–300 K. It is shown that the use of YBa₂Cu₃O_7−δ electrodes in Ba_0.5Sr_0.5TiO₃ film structures ensures that there is no dielectric hysteresis in the paraelectric phase. At the same time, the dielectric nonlinearity is preserved and the dielectric losses are reduced. Pis’ma Zh. Tekh. Fiz. 23, 46–52 (August 12, 1997)     

Influence of phase hardening on transition broadening in a (1−x)NaNbO3−xLiNbO3 system

Dielectric methods are used to study phase-transition broadening in a (1−x)NaNbO₃− xLiNbO₃ system. It is observed that the lowest values correspond to regions of transition between implanted solid solutions and substitutional solid solutions with 0.05≤x≤0.07. It is shown that the degree of broadening of the phase transition may be varied by phase hardening. Pis’ma Zh. Tekh. Fiz. 25, 1–4 (October 26, 1999)     

Reduction in deflections of α-particle orbits in a thermonuclear reactor with an l=3 helical winding

Studies are made of α-particle trajectories in a reactor-scale magnetic system with a three-turn (l=3) helical current winding and an auxiliary current winding generating a vertical magnetic field. It is shown that the deflections of negative and positive free particles relative to the vacuum magnetic surfaces can be reduced by suitably selecting the magnitude and direction of the vertical magnetic field. It is also shown that the deflections of trapped α-particles are reduced under the same conditions. It is particularly important to note that this result was obtained for a system with low aspect ratio. Pis#x2019;ma Zh. Tekh. Fiz. 23, 85–93 (November 26, 1997)     

Nature of the transitional region during the deposition of titanium boride and nitride films on gallium arsenide

Photoluminescence and x-ray photoelectron spectroscopy methods were used to analyze the compositions of the near-junction regions of titanium boride (nitride)-gallium arsenide heterostructures. Data have been obtained for the first time on the formation of Ga_xB1_−x As and GaAs_xN_1−x solid solutions, which play an important role in the formation of the properties and the thermal stability of the experimental structures on the interphase boundary of these structures. Pis’ma Zh. Tekh. Fiz. 25, 71–76 (October 12, 1999)     

Electroluminescence and current-voltage characteristics of n-type porous silicon structures

An investigation is made of a set of n-type porous-silicon structures exhibiting high electroluminescence efficiency and low degradation, and results are presented. These results demonstrate that operating voltages corresponding to those of standard ceramic-metal-oxide-semiconductor technology can realistically be achieved. Pis’ma Zh. Tekh. Fiz. 23, 70–76 (June 12, 1997)