scholarly journals Investigation of electrolysis-related modification of graphene films in biosensors

2021 ◽  
Vol 2103 (1) ◽  
pp. 012103
Author(s):  
I A Eliseyev ◽  
A S Usikov ◽  
S P Lebedev ◽  
A D Roenkov ◽  
M V Puzyk ◽  
...  
Keyword(s):  
Low Frequency ◽  
Frequency Noise ◽  
Kelvin Probe ◽  
Force Microscopy ◽  
Atomic Force ◽  
Graphene Films ◽  
Current Voltage ◽  
Current Voltage Characteristics ◽  
Electrolysis Mode ◽  
Modification Of The Surface

Abstract In this work, the modification of the surface parameters of graphene chips after electrolysis treatment in a NaClO4 aqueous solution has been studied. Two electrolysis modes have been analysed. In the first one, a negative potential (-0.2 V) is applied to the graphene chips, while in the second one the potential is positive (0.8 V). Investigation using a number of techniques including atomic force microscopy, Kelvin probe force microscopy, Raman spectroscopy, measurements of current-voltage characteristics and low-frequency noise has shown that the electrolysis mode with application of a positive potential on graphene chips decreases the 1/f noise and allows one to obtain a uniform surface potential distribution while leaving the graphene structure undamaged. The results of this study help to understand the efficiency and reproducibility of the procedure for electrolysis treatment of graphene chips.

scholarly journals Investigation of the Morphology and Electrical Properties of Graphene Used in the Development of Biosensors for Detection of Influenza Viruses

Biosensors ◽  
2021 ◽  
Vol 12 (1) ◽  
pp. 8
Author(s):  
Natalia M. Shmidt ◽  
Alexander S. Usikov ◽  
Evgeniia I. Shabunina ◽  
Alexey V. Nashchekin ◽  
Ekaterina V. Gushchina ◽  
...  
Keyword(s):  
Low Frequency ◽  
Influenza Viruses ◽  
Virus Concentration ◽  
Frequency Noise ◽  
Force Microscopy ◽  
Atomic Force ◽  
Graphene Films ◽  
Response Versus ◽  
Phosphate Buffered Saline ◽  
Biosensor Response

In this study, we discuss the mechanisms behind changes in the conductivity, low-frequency noise, and surface morphology of biosensor chips based on graphene films on SiC substrates during the main stages of the creation of biosensors for detecting influenza viruses. The formation of phenylamine groups and a change in graphene nano-arrangement during functionalization causes an increase in defectiveness and conductivity. Functionalization leads to the formation of large hexagonal honeycomb-like defects up to 500 nm, the concentration of which is affected by the number of bilayer or multilayer inclusions in graphene. The chips fabricated allowed us to detect the influenza viruses in a concentration range of 10−16 g/mL to 10−10 g/mL in PBS (phosphate buffered saline). Atomic force microscopy (AFM) and scanning electron microscopy (SEM) revealed that these defects are responsible for the inhomogeneous aggregation of antibodies and influenza viruses over the functionalized graphene surface. Non-uniform aggregation is responsible for a weak non-linear logarithmic dependence of the biosensor response versus the virus concentration in PBS. This feature of graphene nano-arrangement affects the reliability of detection of extremely low virus concentrations at the early stages of disease.

Visible Light Photodiodes and Photovoltages from Detonation Nanodiamonds

MRS Advances ◽  
2016 ◽  
Vol 1 (14) ◽  
pp. 971-975
Author(s):  
Bohuslav Rezek ◽  
Stepan Stehlik ◽  
Alexander Kromka ◽  
Jean-Charles Arnault ◽  
Martin Weis ◽  
...  
Keyword(s):  
Open Circuit Voltage ◽  
Green Laser ◽  
Open Circuit ◽  
Detonation Nanodiamonds ◽  
Kelvin Probe ◽  
Force Microscopy ◽  
Current Voltage ◽  
Current Voltage Characteristics ◽  
Energy Conversion Devices ◽  
532 Nm

ABSTRACTMacroscopic and microscopic photovoltage characteristics of detonation nanodiamonds (DNDs) with distinct surface terminations are presented. Organic photodiodes are fabricated based on P3HT+DNDs mixture (50 wt%). We compare effect of hydrogen and oxygen termination of DNDs. Compared to photodiodes without DNDs the current-voltage characteristics of photodiodes with O-DNDs in dark and under AM 1.5 illumination show reduced dark current, and higher photocurrent and open circuit voltage. H-DNDs shunt the photodiodes, which is attributed to their surface conductivity. Kelvin probe force microscopy detects a reproducible photovoltage of around 5 mV generated by a green laser (532 nm) on both types of pristine DNDs. Thus although conductivity of H-DNDs may represent a problem for photodiodes, both types of DNDs alone can function as miniature energy conversion devices.

Effect of High Energy Electron Irradiation on Electrical and Noise Properties of 4H-SiC Schottky Diodes

2018 ◽  
Vol 924 ◽  
pp. 605-608
Author(s):  
Alexander A. Lebedev ◽  
Vitalii V. Kozlovski ◽  
Michael E. Levinshtein ◽  
S.L. Rumyantsev ◽  
John W. Palmour
Keyword(s):  
Electron Irradiation ◽  
Schottky Diodes ◽  
Linear Part ◽  
Low Frequency ◽  
High Energy ◽  
Frequency Noise ◽  
Relaxation Processes ◽  
Low Frequency Noise ◽  
Current Voltage ◽  
Current Voltage Characteristics

Electron irradiation of high voltage Ni/4H-SiC Schottky diodes with the dose Φ=(0.2-7)×1016cm-2 led to increase in the base resistance, appearance of slow relaxation processes at extremely small currents, and increase of the low frequency noise. On exponential part of the current-voltage characteristics and on linear part of current-voltage characteristics in non-irradiated samples, low frequency noise always has the form of the 1/f noise. On linear part of the current-voltage characteristics in irradiated diodes the generation recombination (GR) noise predominates. Temperature dependences of the base resistivity and character of GR noise indicate that mainly Z1/2 center contributes to the change in the parameters of irradiated samples. Capture cross section of this level, obtained from noise measurements, is within the range (8×10-16-2×10-15) cm2 and only weakly depends on temperature.

Atomic Force Microscopy of the Local Electrical Properties of Bilayer Polyaniline-Polystyrene/P(VDF-TrFE) Composite

2021 ◽  
Vol 899 ◽  
pp. 506-511
Author(s):  
Artem V. Budaev ◽  
Ivanna N. Melnikovich ◽  
Vasily E. Melnichenko ◽  
Nikita A. Emelianov
Keyword(s):  
Atomic Force Microscopy ◽  
Electrical Properties ◽  
Polymer Nanocomposite ◽  
Charge Carriers ◽  
Force Microscopy ◽  
Atomic Force ◽  
Current Voltage ◽  
Current Voltage Characteristics ◽  
Piezoelectric Force Microscopy ◽  
Microscopy Techniques

Atomic force microscopy techniques (conductive-AFM, I-V spectroscopy and PFM) were used for characterisation of the local electrical properties of bilayer polyaniline-polystyrene/P(VDF-TrFE) polymer nanocomposite. Observed hysteresis of current-voltage characteristics confirms its memristive properties. It was caused by the influence of the ferroelectric polarization of P(VDF-TrFE) layer, the domain structure of which was visualised by piezoelectric force microscopy on the transport of charge carriers at the interface.

scholarly journals Проводимость композитных пленок на основе проводящего полимера PEDOT : PSS, оксида графена и наночастиц TiO-=SUB=-2-=/SUB=- для контактных слоев перовскитных фотовольтаических структур

2019 ◽  
Vol 61 (4) ◽  
pp. 773
Author(s):  
А.А. Базанова ◽  
В.Н. Петров ◽  
А.Н. Алешин
Keyword(s):  
Titanium Dioxide Nanoparticles ◽  
Composite Films ◽  
Conductive Polymer ◽  
Charge Carriers ◽  
Globular Structure ◽  
Force Microscopy ◽  
Atomic Force ◽  
Current Voltage ◽  
Current Voltage Characteristics ◽  
Perovskite Photovoltaic

AbstractThe electrical properties of composite films based on conductive polymer PEDOT: PSS, graphene oxide (GO), and titanium dioxide nanoparticles (TiO_2) (PEDOT: PSS– TiO_2 and GO–TiO_2) used as contact layers of organic and perovskite photovoltaic structures have been studied. As a result of the study of morphology by atomic force microscopy, it was found that the PEDOT: PSS–TiO_2 and GO–TiO_2 films have a globular structure with a grain size of ~200–300 nm. The current–voltage characteristics of the PEDOT: PSS–TiO_2 and GO–TiO_2 films are measured in the temperature range of 80–300 K, the dependences of the resistivity versus temperature, ρ( T ), which have an activation character, are obtained. It is established that as the temperature decreases, the ρ( T ) dependences show a transition from large values of the activation energy (570 meV and 329 meV) to lower values (25 meV and 2.2 meV) for the PEDOT: PSS–TiO_2 and GO–TiO_2 films, respectively. The mechanisms of transport of charge carriers in the materials studied are discussed.

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