This paper presents results of AC measurements of resistance Rp, phase angle θ, capacity Cp and loss tangent tgδ in dependences on frequency and temperature for InSb-SiO2/Si nanocomposite, immediately after preparation and annealed at 1273 K. The material was obtained by the In+ and Sb+ ions implantation into a SiO2 thin layer. Using obtained parameters frequency dependence of conductivity σ, real and imaginary components of permittivity were determined. This work refers to the hopping mechanism of conductivity and relaxation mechanisms of prepared material.
In this paper results of AC measurements of phase angle θ, capacity Cp and loss tangent tgδ dependences on frequency and temperature for InSb-SiO2 nanocomposite, immediately after preparation are presented. The material was obtained by the implantation of In+ and Sb+ ions into a thin layer of SiO2. Based on mathematical and physical calculations, frequency dependence of conductivity σ and relative permittivity εr were determined. Activation energy of electrons was also calculated. This work refers to the hopping mechanism of conductivity.
In this paper results of measurements of phase angle θ and capacity Cp dependences on frequency and temperature for
(CoFeZr)x(SiOy)(100-x) nanocomposite, immediately after preparation with metallic phase content x=48.36 at.%, are
presented. Based on mathematical and physical calculations, frequency dependence of conductivity was determined.
The material was obtained by ion-beam sputtering using argon ions. The impact of the sputtering process on the
chemical composition of this type of structure was determined. It was observed that material properties change with
frequency increasing from capacitive to inductive type. This is analogous to the voltage resonance in the serial RLC
circuits.
In this paper production process of Zn nanocrystals in SiO2 by using an implantation of high dose zinc ions with energy of 130 keV and annealing process in 700°C were described. Using electron microscopy was established that annealing causes extension of admixtures distribution on depth and zinc nanoparticles size increasing from approx. 1 - 6 nm to 12 - 18 nm.
For prepared material AC conductivity measurements were made in temperatures range from liquid nitride temperature (LNT) to 373 K and at frequencies range from 50 Hz to 5 MHz. Strong frequency dependence on conductivity proves that in this nanocomposite Zn-SiO2 conduction takes place by electron hopping exchange (tunneling) between metallic phase nanoparticles.
It was established that three activation energies of conductivity occurs in temperatures range of LNT – 373 K – in low temperatures ΔE1≈0.001 eV, in medium temperatures ΔE2≈0.025 eV and in higher temperatures area ΔE3≈0.096 eV. This is due to the presence of at least two types of nanoparticles. First there are zinc nanoparticles with zinc oxide coating, second there are nanoparticles without the coating. The highest activation energy occurs during electrons tunneling between nanoparticles with zinc oxide coating. Intermediate activation energy corresponds to tunneling from nanoparticle with coating to nanoparticle without coating or conversely. The lowest activation energy corresponds to electrons hopping between nanoparticles without coatings.
In this paper measurements results of electrical and optical properties of SiNx thin layers are presented. Layers were produced by chemical vapor deposition on n-type (100)-oriented silicon substrates. Measurements were performed for samples directly after deposition and for samples annealed in temperature of 1073 K.
Resistance Rp, capacity Cp, phase angle shift θ and dielectric loss factor tgδ were the measuring parameters on AC in the frequency range from 50 Hz to 5 MHz as a function of measurement temperature from the range 20 K – 373 K. Based on this, the conductivity σ and the activation energy of conductivity were determined. Photoluminescence spectra were recorded at room temperature in the spectral region of 350 – 800 nm using a He-Cd laser source with λ=325 nm.
The influence of annealing on the electrical and optical properties was explained. Current resonance phenomenon and reduction of photoluminescence spectra were observed.
The paper presents frequency f and temperature Tp dependences of conductivity σ, capacitance Cp and phase shift angle θ for the nanocomposite metal-dielectric (FeCoZr)x(CaF2)(100-x). Samples of nanocomposite were produced by ion-beam sputtering in pure argon Ar atmosphere. Partial pressure of gas Ar in the ion source pAr=1.1·10-1Pa. Contains of metallic phase in tested sample is x = 54.6 at.%. Studies carried out by stand to measuring of AC electrical properties of nanocomposites and semiconductors. The measurements have been performed using alternating current within the frequency range of 50 Hz - 1 MHz for measuring temperatures ranging from 77 K to 373 K. On the frequency-temperature dependence of phase shift angle θ at low frequencies phase shift have capacitive character and at high frequencies - inductive. Position of fmin on the frequency dependence on capacitance Cp corresponds exactly to the resonance frequency fR for which the angle θ crosses zero. Analysis of the results showed that phenomena similar to phenomena in conventional circuit RLC occur in the nanocomposite (CoFeZr)54.6(CaF2)45.4. Jumping recharging between the defects leads to the formation of dipoles and consequently to the increase of permittivity. After a time τ electron returns to the first defect and dipole disappears. The formation of inductance in nanocomposite is associated with return jumps of electrons from defect with negative charge to the defect with positive charge, set by the time, which are characterized by low values of activation energy.
In this work, the temperature and frequency dependences of conductivity σ and Arrhenius plots of annealed nanocomposite films containing Fe45Co45Zr10 - based nanoparticles embedded in a doped PbZrTiO3 ferroelectric matrix were studied. The nanocomposites studied were deposited by sputtering with use of argon and oxygen ions in a vacuum chamber. Tested samples were followed by a 15-min annealing process in air in the temperature range of 398 K ≤ Ta ≤ 748 K with steps of 25 K. The σ(f,T) dependences of nanocomposite samples was measured in ambient temperature range of 77 K < Tp < 373 K at frequencies of 50 Hz < f < 1MHz. It was established that nanocomposite sample with metallic phase content x = 55.6 at.% demonstrates strong temperature and frequency dependences, which is typical for a percolation systems. Type of conduction in such nanostructure is defined as dielectric, which may be related with the additional oxidation of metallic nanoparticles during the annealing process. For the tested sample with x = 88.4 at.%. we observe metallic type of conduction, when metallic nanoparticles form a permanent conductive channels in dielectric matrix.
In this paper results of researches of electrical properties of nanocomposites, in which metallic phase is diamagnetic copper in dielectric SiO2 matrix. Materials were obtained by ion-beam sputtering in argon atmosphere. Measured parameters were resistance Rp, capacity Cp and phase angle θ on AC in frequency range 50 Hz - 5 MHz and in measurement temperature function from the range 77 K - 373 K. Based on obtained results occurrence of positive values of phase angle was established. These values were observed in materials immediately after preparation and in annealed in temperature 398 K. Occurrence of non-coil inductance and in some cases voltage resonance phenomena were determined.
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