One of the ways to create highly sensitive gas sensors based on graphene is to modify graphene by forming nanometer-sized channels in it. In this work, ion beam etching was used for these purposes. The necessary doses of Ga+ focused ion beam (FIB) were found to etch graphene. Several different structures based on modified graphene have been manufactured and investigated. A method for manufacturing graphene structures with a width of less than 10 nm by Ga+ FIB has been found. Also, high conductivity for structures of nanogap with polyaniline (PANi) was found, which can be used as selective gas sensing structures. The paper presents the responses of structures with nano-channel of PANi between modified graphene electrodes to different concentrations of ammonia and water.
In this work, we consider the formation of a sensor layer 100 nm thick based on platinum-doped tin oxide. We investigated the method of forming an oxide film using magnetron sputtering Sn and Pt in Ar+O2 plasma. Using X-ray diffraction, it was found that the film consists of nanoscale particles with a metal core. The average size of the nanoparticles forming the film was from 47 to 74 nm The characteristics of the film were measured during additional oxidation in the temperature range from 300 to 700 °C. Thanks to annealing, the resistance of the sensor layer can be varied from 10 kΩ to 100 MΩ at a detection temperature of 300 °C The optimized film has been tested to detect ethanol, acetone, and ammonia at streams of 50, 100, 150 ppm.
Technique based on FIB and PCE for the formation of nanoscale silicon fins on silicon-on-sapphire structures was demonstrated. The stability of the obtained mask to PCE was investigated depending on the dose of ionic exposure. It was found that the Si fin 150 nm in height and a width of less than 40 nm was obtained by implantation of Ga+ ions with a dose of 3 × 1017 to 4 × 1017 см-2. Current-voltage characteristic of contacts to nanosized fins was researched. The gate dielectric Al2O3 2-3 nm thick was deposited by the ALD method. In the created prototypes of the transistor, the length of each channel was 1.2 μm, and the gate - 100 nm. The obtained I-V characteristics prove the good controllability of the channel in the nanosized fin and demonstrate the operability of the devices.
Results of surface morphology and crystalline structure had shown for Ga(Al)N layers which was grown by MBE on 3С- SiC/Si(111) virtual substrates with on-axis and 4° off-axis orientation. Roughness values had increased up to ~7 nm for on-axis and to ~5 nm for 4° off-axis orientation after 560 nm deposition of GaN. Monocrystalline GaN(0002) was verified by ω-rocking curve measurement with FWHM 0.61-0.76° for on-axis and 0.55-0.65° for 4° off-axis orientation. Wafer bow shown the ascending up to ~18 μm for on-axis and ~12 μm for 4° off-axis orientation and tensile strain for all samples had been confirmed.
Stimulated low frequency Raman scattering (SLFRS) in submicron single-crystal diamond films (SCD) with a graphitized layer built-in is investigated. The value of SLFRS frequency shift lies in gigahertz range (8.4-9.3 GHz) and shows the morphological dependence (inverse dependence on the thicknesses of SCD layers). Experimentally estimated SLFRS conversion efficiency and threshold evidence about the coherent phonon mode excitation in submicron SCDs as a result of nonlinear interaction of high-power laser wave with an eigen vibration of nanosized graphitized layer built-in.
Carbon nanotube (CNT) and SiO2 etching effects was studied and was found that using different techniques of focused ion beam (FIB) exposure and using two pass etching leads to a significant difference in the etching rate of CNTs relatively of SiO2 and directly individually oxide itself. The parameters annealing of the structures to remove the effects of the charge arising from the etching of CNT on SiO2 was determined and the effect of the charge on the effects of the deposition of organic molecules from solution was studied. Different behavior of deposition of polar and non-polar polymer materials on charged regions with width less than 100 nm was found. Obtained structures was investigated by SEM, AFM methods and for structures with polyaniline deposited CVC was measured and by comparison with literature and experimental data analysis of polyaniline structuring in nano-scale gap formed with FIB was carried out.
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