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UNIVERSITY OF BUCHAREST
FACULTY OF PHYSICS Guest
2024-11-22 1:24 |
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Conference: Bucharest University Faculty of Physics 2015 Meeting
Section: Solid State Physics and Materials Science
Title:
Memory effects in bare and PEGylated carbon quantum dots
Authors:
I.MIHALACHE (1,2), L. M. VECA (1), M. KUSKO (1), Daniela DRAGOMAN(2)
Affiliation:
(1)National Research and Development Institute in Microtechnologies,Bucharest, Romania
(2)Univ. Bucharest, Faculty of Physics, P.O. Box MG-11, 077125 Bucharest, Romania
E-mail
juliana.mihalache@gmail.com
Keywords:
graphene , carbon dots, nonvolatile memory device, resistance hysteresis
Abstract:
Recent studies have pointed out the potential of different carbonaceous nanomaterials to become promising candidates for future memory and storage applications. Carbon quantum dots used mainly as fluorescence probes are new members of the graphene-type configuration family. This work aims to investigate the electrical behavior of both bare and PEGylated version of carbon quantum dots (CQDs) films deposited by drop-casting on 0.04 mm2 active area of interdigitated electrodes (IDs) microarray. Current–voltage characteristics have been performed at different sweeping rates and voltages showing a significant resistance hysteresis. Stability of the memory effects over a large number of cycles is increased after removing the shallow trapping states of the surface by thermal treatment. Transient currents fitted with biexponential function are used to determine the charging and discharging relaxation times and the charge storage capacity of the carbon dots. Temperature dependence characteristics suggests the presence of a dominant non-hysteretic thermally activated hopping mechanism in the case of bare CQDs, while in the case of surface passivated CQDs the presence of Coulomb blockade with a threshold Vth=2.5 V, as well as other transport mechanisms been simultaneously active.
Acknowledgement:
I. Mihalache acknowledges the support of the Sectorial Operational Programme Human Resources Development, project number POSDRU/159/1.5/S/137750.
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