Experimental and numerical investigation of Poole-Frenkel effect on dynamic R ON transients in C-doped p-GaN HEMTs

In this paper, we investigate the influence of Poole-Frenkel Effect (PFE) on the dynamic R ON transients in C-doped p-GaN HEMTs. To this aim, we perform a characterization of the dynamic R ON transients acquired during OFF-state stress (i.e., V GS,STR = 0 V < V T, V DS,STR = 25–125 V and we interpret the results with the aid of numerical simulations. We find that dynamic R ON transients at room temperature accelerate with V DS,STR 1/2, which is signature of PFE, as further confirmed by the simultaneous decrease of the activation energy (E A) extracted from the Arrhenius plot of the dynamic R ON transients at V DS,STR = 50 V and T = 30–110 °C. Results obtained by means of calibrated numerical simulations reproduce the exponential dependence of transients time constants (τ) on V DS,STR 1/2 and consequent E A reduction only when including PFE enhancement of hole emission from dominant acceptor traps in the buffer related to C doping. This result is consistent with the model that considers hole emission from acceptor traps (rather than electron capture) as the mechanism underlying dynamic R ON increase during OFF-state stress.

Modified Arrhenius Equation in Materials Science, Chemistry and Biology

The Arrhenius plot (logarithmic plot vs. inverse temperature) is represented by a straight line if the Arrhenius equation holds. A curved Arrhenius plot (mostly concave) is usually described phenomenologically, often using polynomials of T or 1/T. Many modifications of the Arrhenius equation based on different models have also been published, which fit the experimental data better or worse. This paper proposes two solutions for the concave-curved Arrhenius plot. The first is based on consecutive A→B→C reaction with rate constants k1 ≪ k2 at higher temperatures and k1 ≫ k2 (or at least k1 > k2) at lower temperatures. The second is based on the substitution of the temperature T the by temperature difference T − T0 in the Arrhenius equation, where T0 is the maximum temperature at which the Arrheniusprocess under study does not yet occur.

Electrochemical properties of La9.33Si6O26(LSO)-La0.8Sr0.2Ga0.8Mg0.2O2.55(LSGM) electrolyte over NiO and La0.1Ca0.9MnO3(LCM) electrodes

The electrochemical properties of La9.33Si6O26(LSO)-La0.8Sr0.2Ga0.8Mg0.2O2.55(LSGM) electrolyte composites have been evaluated over NiO and La0.1Ca0.9MnO3 (LCM) electrodes using symmetric and asymmetrical cells of NiO/LSO-LSGM/NiO and NiO/LSO-LSGM/LCM, respectively. The Nyquist plot obtained from this study suggested that the new electrolyte system exhibits excellent performance over the NiO and LCM electrodes and shows an ideal Randel cell electrical circuit characteristic in both NiO/LSO-LSGM/NiO and NiO/LSO-LSGM/LCM cells. The area-specific resistance (ASR) and, the activation energy (Ea) of NiO/LSO-LSGM/NiO from the Arrhenius plot are lower than the NiO/LSO-LSGM/LCM, which is 0.30 Ω cm-2 and of 0.74 eV versus 0.40 Ω cm-2 with Ea of 0.76 eV, respectively.

Kinematic Viscosity and Electrical Resistivity of a Multicomponent Melt due to Liquid–Liquid Structure Transition

We investigated the kinematic viscosity and electrical resistivity of the multicomponent Fe74Cu1Nb1.5Mo1.5B8.5Si13.5 melt during three heating–cooling cycles. The temperature dependence of kinematic viscosity and electrical resistivity have the anomalous zones in the same temperature range and they are associated with the liquid–liquid structure transition (LLST). The anomalies were explained by changes in the activation energy and the cluster size. As the cluster size decreases, the activation energy decreases, but the viscosity and electrical resistance increase. LLST begins with the cluster dissolution, and as a result, the Arrhenius plot becomes nonlinear in the transition temperature range. After three cycles of heating–cooling, the temperature dependences of the kinematic viscosity and electrical resistance did not qualitatively change, and this allows us to conclude that LLST is thermoreversible. With an increase in the number of thermal cycles, the activation energy of viscous flow decreases, as well as the onset temperature and temperature range of LLST.

Diffusion coefficient calculated by time-lag using the film-roll method

A method for determining the diffusion coefficient by time-lag using the film-roll method for the sublimation diffusion of disperse dye was proposed. A polyethylene terephthalate film-roll coated with dye paste was treated at 170–190°C for various times. A solution consisting of the sum of a steady-state solution and a transient solution was obtained by the homogeneous boundary value problem from a trigonometrical series. The boundary conditions of the steady-state first layer and the steady-state first layer amount of dye were determined from the steady-state concentration distribution. For various diffusion times, the steady-state first layer-passed total amounts of dye that passed through the first layer in the steady-state condition were obtained by subtracting the steady-state first layer amounts from the total amounts. The time-lag was calculated from the linear regression line for the plot of the steady-state first layer-passed total number(X) of positive values against time. The diffusion coefficient was calculated by the boundary conditions of the steady-state first layer and the time-lag. For diffusion at 170°C, 180°C, and 190°C, the correlations of the steady-state first layer-passed total amounts with respect to time were very linear and the reliability of the diffusion coefficients obtained by the time-lag was proved by the good linearity of the Arrhenius plot. The activation energy obtained was 36.8 kcal[Formula: see text]mol−1.

SHELF LIFE OF NORI FROM Gracilaria sp. WITH ALUMUNIUM FOIL PACKAGING BASED ON THE ACCELERATED SHELF LIFE TEST METHOD

This research was conducted at the Laboratory of Fisheries Products Processing, Faculty of Fisheries and Marine Sciences, Padjadjaran University, Jatinangor. The purpose of this research is to determine the shelf life of Nori from Gracilaria sp. with the Accelerated Shelf Life Test (ASLT) method Arrhenius Model using Aluminum Foil packaging. Aluminum foil packaging is a package composed of hermetic, flexible, and opaque metal so that it has high protection properties against water vapor, light, grease and gas. The determination of the shelf life of the ASLT method is carried out using parameters of environmental conditions that can accelerate the process of product quality degradation, namely by storing the product at several temperatures above normal storage temperature. The observations used in determining the shelf life of Gracilaria sp. using a sensory test and a water content test with storage for 35 days, at a temperature of 25oC and 35oC. The result of the Arrhenius model calculation, the appearance parameter is selected as the critical parameter because it has the lowest Activation Energy (Ea) in determining the shelf life of Gracilaria sp. which is packaged using PE plastic. The results show that the parameters used to determine the shelf life of the product are the taste parameters based on the order 1 reaction with the Arrhenius Plot Ln K = 0.026 – 1318.4 (1 / T) and Ea of 2619.66 Kj/mol. The shelf life of Nori Gracilaria sp. if stored at 25oC temperature is 89 hari 7 jam.

Влияние температуры отжига на кинетику процесса алюминий-индуцированной кристаллизации тонких пленок аморфного субоксида кремния

In this work, the kinetics of aluminum-induced crystallization (AIC) of non-stoichiometric silicon oxide a-SiO0.25 was investigated for annealing temperatures of 370, 385 and 400 °C, as a result of which thin films of polycrystalline silicon were obtained. It is shown that for low annealing temperatures, the surface morphology of the crystalline material is represented by dendric structures corresponding to the growth model with diffusion-limited aggregation. In addition, with an increase in the annealing temperature, the nucleation density increases from 3 to 53 mm–2. From the Arrhenius plot, the activation energy of the AIC process of a-SiO0.25 was obtained for the first time, which was 3.7±0.4 eV.