Nikolai Kovalchuk

Belarusian State University of Informatics and Radioelectronics · Research Laboratory 4.6 for Integrated micro- and nano-systems

In this article we present the results of micro-Raman studies of graphene grown on copper foil surface by atmospheric pressure CVD using decane as precursor, nitrogen as carrier gas with zero flow of hydrogen. Analysis of Raman spectroscopy data showed that film contains spots with single layer thick graphene. We observed significant blue shift of...

Linear G peak position temperature dependence in Raman spectra of graphene synthesized by chemical vapor deposition from decane on copper (220) with a shift factor of (5.4±0.4)∙10-2 cm-1K-1 was observed. The obtained value is substantially in excess of values previously obtained by other authors for graphene, and was associated with the substrate i...

We present Raman studies of graphene films grown on copper foil by atmospheric pressure CVD with n-decane as a precursor, a mixture of nitrogen and hydrogen as the carrier gas, under different hydrogen flow rates. A novel approach for the processing of the Raman spectroscopy data was employed. It was found that in particular cases, the various para...

The paper reports on the first successful fabrication of Co-graphene composites by electrochemical deposition of Co nanoparticles (NPs) on the sheets of twisted graphene. Characterization of the surface morphology and element mapping of twisted graphene decorated with Co NPs by transmission and scanning electron microscopy in combination with the e...

We demonstrate the growth features of III-nitrides on graphene buffer layers obtained by the CVD method on a copper catalyst with different dominant grain orientations. The reflection high-energy electron diffraction technique (RHEED) is used to map the 2D reciprocal space structures of graphene buffers and growing nitride layers. The RHEED recipro...

Application of magnetic metal/graphene hybrid structures in magnetosensorics requires the formation of high-quality low-ohmic (barrier-free) contacts and understanding of mechanisms of electric charge transfer near and through the metal/graphene contact area. In present paper we fabricate samples of twisted graphene electrochemically decorated with...

To take advantage of the graphene appealing electronic properties, in this work we present a photodetector (PD) based on graphene/n-silicon heterojunction (GSH). In this device, graphene acts as light transmitter, counter electrode junction element and photocarrier collector. The photodetector has been provided with metal contacts allowing either p...

The possibility of using chemical vapor deposition (CVD) graphene as a 2D buffer layer for epitaxial growth of III-nitrides by plasma assisted-MBE on amorphous substrates (SiO 2 prepared by thermal oxidation of Si wafer) was investigated. The comparative study of graphene-coated parts of the wafers and the parts without graphene was carried out by...

Photodetectors (PDs) based on single-walled carbon nanotube film/silicon and graphene/silicon heterojunctions have been realized for fast applications. We investigated the response of the PDs to femtosecond pulsed laser using a three-electrode configuration for photoconductive operations. Both junction PDs exhibit rise times of some nanoseconds, de...

We registered surface enhanced Raman scattering (SERS) spectra of the human lactoferrin molecules adsorbed on a silvered porous silicon (por-Si) from 10−6–10−18 M solutions. It was found that the por-Si template causes a negative surface potential of silver particles and their chemical resistivity to oxidation. These properties provided to attract...

Raman spectroscopy was used to study the structural properties of graphene synthesized by chemical vapor deposition using decane (C10H22) as a precursor at various hydrogen concentrations. Reduction of the carrier gas flow rate from 150 cm3/min to zero changes the average spacing between the defects from 53 to 212 nm and the average grain size from...

Raman spectroscopy was used to study the structure of graphene synthesized from methane by chemical vapor deposition at atmospheric pressure and transferred to a SiO 2 /Si substrate using various transfer and polymer-removal methods. It was found that the dependences of the 2D peak positions on the G peak positions of the studied samples were well-...