Abstract-The effects of dead space (the minimum distance travelled by a carrier before acquiring enough energy to impact ionize) on the current impulse response and bandwidth of an avalanche multiplication process are obtained from a numerical model that maintains a constant carrier velocity but allows for a random distribution of impact ionization path lengths. The results show that the main mechanism responsible for the increase in response time with dead space is the increase in the number of carrier groups, which qualitatively describes the length of multiplication chains. When the dead space is negligible, the bandwidth follows the behavior predicted by Emmons but decreases as dead space increases.
AbstractPoly(methyl methacrylate) (PMMA)-based polymer electrolyte membranes are prepared through the solution cast method, with PMMA:ethylene carbonate (EC):LiCF3SO3:Al2O3 weight ratio of 55.13:18.34:24.5:2. The effect of Al2O3 filler grain sizes of 50 nm and 10 μm on the polymer electrolytes was studied in this work. From the Cole-Cole plot obtained through electrochemical impedance spectroscopy, the highest ionic conductivity for 50-nm Al2O3 in the PMMA-LiCF3SO3-EC-Al2O3 sample was measured as 1.52 × 10−4 S/cm at room temperature. The bonding formation among the host polymer and other additives in the polymer electrolytes has been studied using Fourier transform infrared spectroscopy. A strong occurrence of CH3 stretching mode has proven that nano size Al2O3 results in a much stronger bonding effect with the host polymer. The particle sizes were calculated by applying the Debye-Scherrer equation from the X-ray diffraction results. This work considers the effect of instrument broadening to further improve the accuracy of particle broadening for particle size calculation. The average particle size of nano size Al2O3 in the PMMA sample is calculated as 2.9693 nm. Moreover, a higher amorphousity level obtained from nano size filler polymer electrolyte of 98.5% computed from differential scanning calorimetry thermograms had also explained the achievement of high ionic conductivity in this work.
PMMA-based polymer electrolytes with LiCF3SO3 lithium salt, EC plasticizer, and SiO2 filler are prepared using the solution cast method. SiO2 filler sizes at 10 μm and 63 μm are used to estimate the particle size in the polymer electrolytes system. EIS analysis calculates ionic conductivity based on the Cole-Cole plot generated in frequency ranging from 0.1 Hz to 1 MHz. The calculation results in ionic conductivity at 1.44 × 10 -4 S/cm and 8.1 × 10 -5 S/cm for 10 μm and 63 μm SiO2 filler, respectively. FWHM measurement is performed for each diffraction peak based on the XRD spectra. Debye-Scherrer equation is used to estimate the resultant particle size. Peak broadening effect caused by the instrument is considered for a more accurate estimation of particle size in the polymer electrolyte system. Linear regression is employed to determine the average particle size arising from these diffraction peaks. The results showed that larger filler size results in the formation of a larger particle size.
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