Abstract:
The results of studies of the dependences of current on applied voltage, low-frequency noise and impedance characteristics in thin films based on carbon quantum dots (CQDs) obtained from L-Lysine using microwave technology, which allows the synthesis of CQDs with an average size of less than 10 nm, are presented. The impedance spectroscopy results show that the Cole–Cole plots are in good agreement with the equivalent circuit model and represent the series resistance, recombination resistance, and geometric capacitance, respectively, which arise from charge storage, charge transfer resistance, and/or additional interfacial electronic states. The mechanisms of current flow, the formation of current noise, and the occurrence of defects are considered. In the frequency range under study ($f\le$ 8000 Hz), the $1/f$ noise associated with fluctuations in the charge carrier density is most clearly visible. A possible mechanism responsible for the transport of charge carriers in CQDs films is discussed. The results obtained make it possible to predict the properties of optoelectronic devices based on CQDs.
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