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The spectrum of localized hole states (traps) in amorphous silicon nitride, a-Si3N4, is experimentally studied using the method of thermally stimulated depolarization. The experiment is compared with theoretical calculations using three models of the energy spectrum of traps: discrete spectrum (monoenergetic trap), continuous spectrum, and Gaussian trap distribution. The experiment is quantitatively described by a model of a discrete spectrum of traps with an energy of 1.15 eV and a width of no more than 0.01 eV. In the case of a continuous and Gaussian spectrum of traps, the contribution to depolarization is made by the deepest traps. The blurring of the trap energy level in a-Si3N4 due to the absence of long-range order (fluctuations in the Si–N bond length and fluctuations in the N–Si–N and Si–N–Si angles) does not exceed 0.01 eV. [ABSTRACT FROM AUTHOR]

A series of laboratory and numerical experiments have been performed to study the process of the surface water cooling. The process of the submergence of an ensemble of jets (a thermal-like structure) or a negative buoyancy flux was recorded using digital cameras (∼2 and 10 Hz). Quantitative estimates of the structure and dynamical features of the initial phase of the submergence of a density front of the ensemble of jets were obtained. These estimates were compared with the previous results of the study of individual thermals. It was found that the deepening velocity is characterized by the nonlinear dependence from the submergence depth in time of both the thermals and the density front of the ensemble. The numerical calculations also showed nonlinearity in this dependence. The process of submergence of the density front was divided into three stages, which were described for the first time. The deepening velocity of the density front of the ensemble of jets was ∼0.15 cm/s. The results are qualitatively consistent with the theoretical estimates of the evolution of the free convection. The observed laboratory flows have the laminar nature of convective movements (Reynolds numbers ranging from 3 to 60). A geometric model was proposed to describe linear quantity of both the thermal and jet. It was shown that the effects of turbulence on the seawater measurements were caused externally and not related to the process of the surface water cooling. Thus, it is assumed that either thermal or saline turbulence dominates over free convection conditions. This conclusion has an important role in the study of the heat exchange process in ocean models. [ABSTRACT FROM AUTHOR]

Amorphous aluminum oxide a-Al2O3 deposited by atomic layer deposition (ALD) is widely used in nonvolatile memory devices. In this paper, the leakage current dependence on the ALD synthesis temperature is investigated by six charge transport models: Schottky effect, thermally assisted tunneling at a contact, Frenkel effect, Hill-Adachi model of overlapping Coulomb potentials, Makram-Ebeid and Lannoo multiphonon isolated trap ionization model, and Nasyrov–Gritsenko model of phonon-assisted tunneling between neighboring traps. It is shown that the leakage current exponentially increases with the ALD synthesis temperature, which is related to the increase in trap concentration. [ABSTRACT FROM AUTHOR]

Recently ferroelectric properties have been found in hafnia-based nanosized films. Such films are of the utmost interest for development of a universal memory, which combines the advantages of random access memory and flash memory. The paper studies optical properties of hafnia-zirconium oxide films H-fxZryO2 and lanthanum-alloyed hafnia-zirconium oxide films La:HfxZryO2. Fluctuations of thickness in HfxZryO2 do not exceed 3.5%, fluctuations of thickness in La:HfxZryO2 films—3.2%. Optical properties are analyzed based on effective-medium theory. According to effective-medium theory data, HfxZryO2 films contain 46% HfO2, 54% ZrO2, La:HfxZryO2 films contain 47.5% HfO2, 52.4% ZrO2, 2.5% La2O3. [ABSTRACT FROM AUTHOR]

Silicon oxynitride films of various compositions were grown by the plasma-enhanced chemical deposition method using a setup with remote plasma and an inductive excitation from a gas mixture of 10% monosilane (diluted with argon) and nitrogen in the presence of residual oxygen in working gas mixtures. The high-frequency generator power (13.56 MHz) was varied in the range of 50–150 W. The samples composition was studied using x-ray photoelectron spectroscopy. A comparison of the experimental Si 2p photoelectron spectrum with the calculation showed that, at a low generator power (50 W), the short-range order in silicon oxynitride films is better described by the "random mixture" model. As the generator power is increased (100 W and higher), the excess silicon content in a silicon oxynitride film is decreased, and the short-range order is better described by the "random bonding" model. On metal–insulator–semiconductor-structures based on the silicon oxynitride films obtained, measurements of current–voltage characteristics were carried out, and the resistive switching of the obtained structures is studied in the present contribution. It is found that, in films in which the short-range order is described by the random bonding model, a stable switching in the bipolar regime is observed. [ABSTRACT FROM AUTHOR]