Транспорт дырок в полистироле и поликарбонате, допированных полярными допантами
Hole transport in PS and PC doped with low molecular-mass-dopants with dipole moments larger than 3D is investigated. Both near-surface and bulk charge-carrier generation techniques are used. There is good agreement between the experimentally measured values of hole mobility and the published data. It is shown that, for the investigated systems, the hole transport is none quilibrium and is well described by the multiple-trapping model with the Gaussian trap distribution over energy. The presence of a flat plateau on the time-of-flight curves does not necessarily mean establishment of the quasi-equilibrium hole transport in the system.
29.19.23 Теория электрических свойств твердых тел
The shape of time-of-flight curves in the mode of subsurface irradiation of samples with lowenergy electrons is analyzed for free_standing films of a typical molecularly doped polymer of different thicknesses (11–45 μm). Special attention is paid to comparison of curves registered for both sides of the samples. The data confirm the hypothesis that the defective layer is formed owing to sublimation of dopant molecules during sample preparation and qualitatively agree with predictions of the two_layer multiple_trapping model.29.19.23 Теория электрических свойств твердых тел 29.19.25 Взаимодействие проникающего излучения с твердыми телами
Theoretical and experimental studies of the carrier transport in molecularly doped polymers (MDPs) have been reported. Theoretical analysis uses the multiple trapping (MT) model with an exponential and Gaussian trap distributions. Experimental technique is based on an electron gun technology enabling one to conduct time of flight measurements using the surface and the bulk carrier generation. The list of MDPs tested includes both polar and non_polar systems, some with varying dopant oncentration. Experimental results are compared to the MT model predictions as well as the mainstream theories of the hopping conduction in MDPs.
In Proceedings of the conference participants are presented on the following topics: 1) Lasers and Optics 2) Solid State Physics 3) Nuclear Physics 4) The generation and use of X-rays 5) Plasma Physics and particle beams 6) Astrophysics
The dynamics of a two-component Davydov-Scott (DS) soliton with a small mismatch of the initial location or velocity of the high-frequency (HF) component was investigated within the framework of the Zakharov-type system of two coupled equations for the HF and low-frequency (LF) fields. In this system, the HF field is described by the linear Schrödinger equation with the potential generated by the LF component varying in time and space. The LF component in this system is described by the Korteweg-de Vries equation with a term of quadratic influence of the HF field on the LF field. The frequency of the DS soliton`s component oscillation was found analytically using the balance equation. The perturbed DS soliton was shown to be stable. The analytical results were confirmed by numerical simulations.
By using superconducting quantum interference device (SQUID) magnetometry, we investigated anisotropic high-field (H less than or similar to 7T) low-temperature (10 K) magnetization response of inhomogeneous nanoisland FeNi films grown by rf sputtering deposition on Sitall (TiO2) glass substrates. In the grown FeNi films, the FeNi layer nominal thickness varied from 0.6 to 2.5 nm, across the percolation transition at the d(c) similar or equal to 1.8 nm. We discovered that, beyond conventional spin-magnetism of Fe21Ni79 permalloy, the extracted out-of-plane magnetization response of the nanoisland FeNi films is not saturated in the range of investigated magnetic fields and exhibits paramagnetic-like behavior. We found that the anomalous out-of-plane magnetization response exhibits an escalating slope with increase in the nominal film thickness from 0.6 to 1.1 nm, however, it decreases with further increase in the film thickness, and then practically vanishes on approaching the FeNi film percolation threshold. At the same time, the in-plane response demonstrates saturation behavior above 1.5-2T, competing with anomalously large diamagnetic-like response, which becomes pronounced at high magnetic fields. It is possible that the supported-metal interaction leads to the creation of a thin charge-transfer (CT) layer and a Schottky barrier at the FeNi film/Sitall (TiO2) interface. Then, in the system with nanoscale circular domains, the observed anomalous paramagnetic-like magnetization response can be associated with a large orbital moment of the localized electrons. In addition, the inhomogeneous nanoisland FeNi films can possess spontaneous ordering of toroidal moments, which can be either of orbital or spin origin. The system with toroidal inhomogeneity can lead to anomalously strong diamagnetic-like response. The observed magnetization response is determined by the interplay between the paramagnetic-and diamagnetic-like contributions.
Radiation conditions are described for various space regions, radiation-induced effects in spacecraft materials and equipment components are considered and information on theoretical, computational, and experimental methods for studying radiation effects are presented. The peculiarities of radiation effects on nanostructures and some problems related to modeling and radiation testing of such structures are considered.