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Transport and noise characteristics of MIS structure and their aplication on the NbO capacitors
Velísek, Martin ; Majzner, Jiří (referee) ; Sedláková, Vlasta (advisor)
The aim of my work was the study of niob-oxide capacitor properties. Capacitor structure NbO-Nb2O5-MnO represents the M-I-S structure where NbO anod has metalic conductivity and MnO2 is semiconductor. The capacitor connected in the normal mode with the positive voltage on the NbO anode represents the MIS structure connected in the reverse direction, when the applied votlage increases the potencial barrier between the insulator Nb2O5 and semiconductor (MnO2). The charge carrier transport is the Nb2O5 layer is determined by the Poole-Frenkel mechanism and tuneling in the normal mode. Poole-Frenkel mechanism of the charge carrier transport is dominant for low electric field in the dielectric layer; tunneling current is dominant for the high electric field. We can estimate the effective thickness of the dielectric layer and the ratio between the Poole-Frenkel and tunelling current from the modeling of measured VA characteristics.
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Lead-Acid Battery Evaluation Based On Opencircuit Voltage Fluctuation Measurement
Kuparowitz, Tomáš ; Kuparowitz, Martin
The state of charge and the state of health are two crucial parameters of batteries. Current state of the art methods of their estimation include some as simple as measuring open circuit voltage, all the way to fuzzy logic estimation and constant online battery overview. Some main problems of such methods are either the length of single parameter evaluation cycle, or their inherent inaccuracy due to limitations in battery manufacture precision. This article proposes novel method of the lead-acid battery state of the health estimation, based on open circuit noise measurement. It reports the nature of changes in low frequency noise spectral density, that occur after catastrophic self-discharge failure or avalanche voltage drop in lead-acid batteries.
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Transport and noise characteristics of MIS structure and their aplication on the NbO capacitors
Velísek, Martin ; Majzner, Jiří (referee) ; Sedláková, Vlasta (advisor)
The aim of my work was the study of niob-oxide capacitor properties. Capacitor structure NbO-Nb2O5-MnO represents the M-I-S structure where NbO anod has metalic conductivity and MnO2 is semiconductor. The capacitor connected in the normal mode with the positive voltage on the NbO anode represents the MIS structure connected in the reverse direction, when the applied votlage increases the potencial barrier between the insulator Nb2O5 and semiconductor (MnO2). The charge carrier transport is the Nb2O5 layer is determined by the Poole-Frenkel mechanism and tuneling in the normal mode. Poole-Frenkel mechanism of the charge carrier transport is dominant for low electric field in the dielectric layer; tunneling current is dominant for the high electric field. We can estimate the effective thickness of the dielectric layer and the ratio between the Poole-Frenkel and tunelling current from the modeling of measured VA characteristics.
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