New types of transformer frequency dividers

Conclusions The dividers described above can be made for dividing high voltages (2–3.5 kV) over a wide frequency range (20 Hz–200 kHz). The divider with its variable input resistance provides a convenient and rapid reading of the input voltage for a known output voltage and, owing to this, it can be used in thermoelectric voltage comparators.Translated from Izmeritel'naya Tekhnika, No. 1, pp. 59–61, January, 1972.     

Current–Voltage Characteristics of TlInX2–TlSmX2 (X = S, Se, Te) Alloys

The steady-state current–voltage characteristics of TlInX₂–TlSmX₂ alloys were measured as a function of sample composition and thickness. The results demonstrate that the alloys studied exhibit threshold switching. The threshold voltage decreases with increasing mean atomic weight and can be stabilized by heat treatment. The most stable current–voltage characteristics are obtained for thin-film samples.     

Non-linear current–voltage characteristics related to native defects in SrTiO3 and ZnO bicrystals

SrTiO₃ and ZnO bicrystals with various types of boundaries were fabricated in order to examine their current–voltage characteristics across single grain boundaries. Their grain boundary structures were also investigated by high-resolution transmission electron microscopy. In Nb-doped SrTiO₃, electron transport behaviors depend on the type of boundaries. Random type boundaries exhibit highly non-linear current–voltage characteristics, while low angle boundaries show a slight non-linearity. On the contrary, undoped ZnO does not exhibit non-linear current–voltage characteristics in any type of boundaries including random ones. It is suggested that the differences observed in current–voltage properties between the two systems are mainly due to the difference in the accumulation behavior of acceptor-like native defects at grain boundaries. A clear non-linearity is obtained by means of Co-doping even for the highly coherent Σ1 boundary in a ZnO bicrystal. This is considered to result from the production of acceptor-like native defects by Co-doping.     

Capacitance and current–voltage simulation of EEPROM technology highly doped MOS structures

In this work, experimental capacitance (C–V) and current–voltage (I–V) data of electrically erasable programmable read-only memories (EEPROM) technology MOS structures were simulated. A specific test structure called a double-poly MOS capacitor reproducing the different stacked layers of an EEPROM cell state transistor has been used (7.2 nm SiO₂ oxide, highly doped n⁺ substrate). Our aim was to research the most relevant model that allows a reliable extraction of electrical parameters and that could be easily introduced in industrial EEPROM devices simulators. To simulate C–V data, different classical and quantum models for the estimation of the semiconductor charge have been considered. Due to the substrate high-doping level and to the occurrence of Fowler–Nordheim (FN) injection, the available voltage domain for C–V recordings is reduced, which does not allow to distinguish between the different theoretical models predictions. I–V data were simulated using the classical FN model in which the oxide electric field–gate voltage relationship was extracted from the different C–V models mentioned above. Moreover, an iterative procedure we have proposed in a previous study has also been considered. It is shown that all the models lead to very comparable I–V simulations. These results let us conclude that the very time-consuming resolution of Schrödinger–Poisson coupled equations in a complete quantum approach is not necessary and that classical models remain sufficiently precise and reliable.     

Effect of reactive ion etching and post-etching annealing on the electrical characteristics of indium-tin oxide/silicon junctions

Indium tin oxide (ITO) films were deposited onto p-type Si wafers with radio frequency (r.f.) magnetron sputtering. The effect of the silicon surface treatment with reactive ion etching (RIE) on the current–voltage (I–V) and capacitance–voltage (C–V) characteristics of the ITO/Si junction are investigated. When the Si substrate is etched by RIE prior to the deposition of ITO film, the I–V characteristics of the ITO/p-Si junction transfer from an ohmic contact for the unetched-Si to a rectifying contact for the etched Si. In addition, the barrier height, ideality factor, and series resistance increase with increasing etching power. This is attributed to the net positive ion charge and defects on the damaged surface. Thermal annealing can eliminate the damage caused by RIE. The I–V curves of ITO/etched p-Si become more ohmic as samples are annealed in N2 at 300 °C. Secondary ion mass spectroscopy (SIMS) depth profiles indicate that some impurity defects migrate and/or disappear after post-etching annealing. © 1998 Chapman & Hall     

A Method of Measuring Current–Voltage Characteristics Based on the Hammerstein–Chebyshev Model

A method of measuring the current–voltage characteristics of nonlinear components is proposed, which involves applying a sinusoidal voltage to the object being measured, finding the Fourier spectrum to read out the output current, and a calculation using the spectrum of the coefficients of the expansion of the measured characteristic in Chebyshev polynomials. The properties of the Hammerstein–Chebyshev model are considered, a block diagram of a measuring instrument is presented, and recommendations are made for minimizing the systematic errors due to approximating their characteristics by Chebyshev polynomials.     

Portable Comparison Standard Based on the Josephson Effect

A comparison standard is developed in the form of a small voltage standard based on the Josephson effect whose metrological characteristics make it possible to compare stationary voltage standards with uncertainty less than 10^–9. The standard was used in key comparisons of national voltage standards within the framework of Euromet Project N 723.__________Translated from Izmeritelnaya Tekhnika, No. 2, pp. 48–51, February, 2005.     

Application of High-Speed Laser Polarimetry to Noncontact Detection of Phase Transformations in Metals and Alloys at High Temperatures

A high-speed laser polarimetry technique, developed recently for the measurement of normal spectral emissivity of materials at high temperatures, was used to detect solid–solid and solid–liquid phase transformations in metals and alloys in millisecond-resolution pulse-heating experiments. Experiments were performed where normal spectral emissivity at 633 nm was measured simultaneously with surface radiance temperature, resistance, and/or voltage drop across the specimen. It was observed that a phase transformation, as indicated either by an arrest in the specimen radiance temperature or changes in the resistance and/or voltage drop, generally caused a change in normal spectral emissivity. Experiments were conducted on cobalt, iron, hafnium, titanium, and zirconium to detect solid–solid phase transformations. Similar experiments were also performed on niobium, titanium, and the alloy 85titanium–15molybdenum (mass%) to detect solid–liquid phase transformations (melting).     

Use of transportable voltage measures for transfer of emf and dc voltage units

The possibility is shown of using transportable solid- state voltage measures for the transfer of emf and dc voltage units in the highest link of the GOST 8.027- 89 calibration scheme with an error (5–6)·10^–7.Translated from Izmeritel'naya Tekhnika, No. 9, p. 43, September, 1993.     

Quantum Interference above 4.2 K in a GaAl0.3As0.7/GaAs Aharonov-Bohm Ring

Magneto-conductance measurements of a micron sized GaAI_0.3As_0.7/GaAs Aharonov–Bohm devicehas been performed at temperatures above T=4.2 K, inthe regime where only a few transverse modes are occupied. Wefind that the Aharonov–Bohm oscillations are still visible atthese relatively high temperatures. The electron density ofthe Aharonov–Bohm device was during the measurementscontrolled via a gate voltage applied to a small stub whichwas attached to one arm of the ring. Due to this highlyasymmetric gate configuration the electron density in the ringis strongly asymmetric, and hence an oscillating conductanceas a function of gate voltage is expected—in analogy withthe Mach–Zender interferometer.     

Bias voltage dependence properties of cadmium oxide films deposited by d.c. reactive magnetron sputtering

Cadmium oxide films were grown on glass substrates using d.c. reactive magnetron sputtering technique by sputtering from a metallic cadmium target in an oxygen partial pressure of 1×10^–3 mbar under various substrate bias voltages. The substrate bias voltage significantly influences the crystallographic structure of the deposited films. The influence of substrate bias voltage on the electrical and optical properties of the films was systematically studied. The films formed at a substrate temperature of 473 K and bias voltage of –80 V showed an electrical resistivity of 1×10^–3 cm, optical transmittance of 86%, optical band gap of 2.47 eV and a figure of merit of 7×10^{–3 –1}.     

Compound semiconductor interfaces obtained by direct wafer bonding in hydrogen or forming gas

A technique of direct bonding wafers up to 6-inch diameter without mechanical load after being heated to elevated temperatures in H₂ or in non-flammable forming gas (5% H₂/95% N₂) was applied to GaAs and GaAs/GaP. Electron microscopy revealed crystallographic bond interfaces containing the typical dislocation network. The density of dislocations can be easily chosen below a limit adverse to electrical properties. Current–voltage characteristics of doped GaAs wafer pairs showed ohmic behavior of p–p and n–n junctions, whereas p–n diodes showed 2 to 3 V breakdown voltage as well as an ideality factor between 1.0 and 1.8.     

Primary solid-state batteries constructed from copper and indium sulphides

Copper and indium sulphides were prepared by a chemical precipitation method and further characterized. Low-cost, easily fabricated dry cells were constructed by gluing the metal sulphides on a magnesium foil using a polymer electrolyte. The efficiency, energy densities and cell voltage values of the cells were in the range 8.1–6.2 mWh cm^–3, 150–77 mWh g^–1 and 1.58–1.21 V, respectively.     

A Method of Calibrating Standard Voltage Dividers up to 1000 V

A method of calibrating a resistive voltage divider for voltage ratios of 1000 V/10 V and 100 V/10 V with an uncertainty at the level of 10⁻⁷ is developed. The method enables a calibration to be carried out at the working voltage of the divider and can be used to calibrate a transportable voltage ratio standard when carrying out CCEM-K8 key comparisons.__________Translated from Izmeritel’naya Tekhnika, No. 4, pp. 52–57, April, 2005.     

Precision comparator for measuring in the range 1–10 mV

Conclusions Investigations of the cascade comparator have shown that the error in measuring the ratio of the SS emf to the JJ voltage (1 mV) does not exceed 4·10^–7. For larger JJ voltages the error decreases, and for 8 mV it does not exceed 5·10^–8. This error is determined mainly by the response threshold of the NFK-2 nanovoltmeter which serves as a null detector in comparing the measured voltage to voltage drops across the comparator lower arm. When this voltmeter is replaced by more sensitive instruments the above error can be reduced to 10^–7 and 2·10^–8, respectively.The comparator can be used for precise measurements in various physical investigations, e.g., in measuring temperature by means of platinum resistance thermometers, etc., when the error must not exceed 10^–7.Deceased.Translated from Izmeritel'naya Tekhnika, No. 5, pp. 53–56, May, 1980.     

Atomic layer deposition of HfO2 thin films and nanolayered HfO2–Al2O3–Nb2O5 dielectrics

Smooth, 4–6-nm thick hafnium oxide films were grown by atomic layer deposition from HfI₄ or HfCl₄ and H₂O on SiO₂/Si(1 0 0) substrates at 300 °C. Non-uniform films were obtained on hydrogen-terminated Si(1 0 0). The stoichiometry of the films corresponded to that of HfO₂. The films contained small amounts of residual chlorine and iodine. The films deposited on SiO₂/Si(1 0 0) were amorphous, but crystallized upon annealing at 1000 °C. In order to decrease the conductivity, the HfO₂ films were mixed with Al₂O₃, and to increase the capacitance, the films were mixed with Nb₂O₅. The capacitance–voltage curves of the Hf–Al–O mixture films showed hysteresis. The capacitance–voltage curves of HfO₂ films and mixtures of Hf–Al–Nb–O were hysteresis free.     

Equipment for testing stability of the standard cells emf on the basis of the Josephson effect

Conclusion The equipment developed for testing the stability of standard cells on the basis of the Josephson's effect is suitable for detecting absolute variations in the SS emf of the order of 0.1 V, and this exceeds considerably the potentialities of the now existing method based on the application of current balances. It is assumed that sensitivity can be raised by increasing up to 10 mV the voltage across a single Josephson unit or across several of them connected in series. Thus, there exists an actual possibility of producing a new voltage standard with a relative instability in reproducing the values of unit voltages of the order of 5·10^–7% and a reproduction error determined by the precision in calculating the value of the magnetic field quantum h/2e and by other physical constants (i.e., of the order of 5·10^–5%).Translated from Izmeritel'naya Tekhnika, No. 4, pp. 59–61, April, 1976.     

PVK/Alq3 organic light emitting diodes obtained by evaporation

Poly(N-vinycarbazole) (PVK)/tris(8-hydroxy)-quinoline-aluminum (Alq₃) bilayer diodes were deposited by vacuum evaporation onto SnO₂ coated glass substrates. After deposition of an aluminum upper electrode, the diodes were studied by current–voltage (I–V) and electroluminescence–voltage (EL–V) measurements. It is shown that the luminescence of the structures should be attributed to Alq₃. However the presence of evaporated PVK allows us to decrease the barrier height at the interface SnO₂/PVK because of the localized states induced in the PVK band gap during the evaporation which allows multistep tunneling effect. The optimum Alq₃ thickness is shown to be about 75 nm.     

High-temperature superconducting SQUID as calibrator of ac voltage dividers and LF voltmeters

The performance of a radio-frequency SQUID made of high-temperature superconducting ceramics as a calibrator of ac voltage dividers and LF voltmeters at frequencies up to 1 MHz is investigated. The measurement technique and errors are analyzed. The obtained results suggest that in principle the high-temperature superconducting device can reproduce the voltage divider scale with an error less than 10^–3 dB within an input signal range from several microvolts to several volts.Translated from Izmerital'naya Tekhnika, No. 9, pp. 47–50, September, 1995.     

Vibrations of the electric field strength of arcs at the axis of a submerged jet

It is shown experimentally that pulsed variation of the arc shape produces damped voltage and field strength vibrations.Translated from Inzhenerno-Fizicheskii Zhurnal, Vol. 48, No. 4, pp. 666–670, April, 1985.