Monitoring the doping of graphene on SiO₂/Si substrates during the thermal annealing process

Abstract

It is the temperature of annealing after the transfer of CVD graphene influencing the doping and compression level, and thus the various Raman peak positions reported in the literature.

Graphene material preparation through thermal treatment of graphite oxide electrochemically synthesized in aqueous sulfuric acid

“…[2][3][4][5] A variety of methods have been employed to produce graphene materials, however exfoliation by mechanical (ball milling, micromechanical cleavage, sonication) 5 as well as electrochemical treatment [6][7][8] appear to be most oen used. Graphene materials can also be synthesized by other methods, such as chemical or electrochemical reduction of graphene oxide, 2,7 thermal exfoliation of graphite/graphene oxide, [9][10][11] unzipping of carbon nanotubes, 12 chemical vapour deposition, 13 or plasma assisted method. 14 Properties of graphene materials being strongly related to the method used as well as conditions applied, determine its practical application, i.e.…”

Graphene‐SiO2 Interaction from Composites to Doping

“…In addition to doping, the increase of temperature, needed during the treatment, could induce some effects arising from the different thermal expansion coefficients of Gr and substrate . To investigate this effect treatments similar to the one carried out with oxygen but employing different gases have been applied to various Gr samples on SiO 2 /Si.…”

“…Indeed, some effects on the Gr properties can be related to stress induced by differences of thermal expansion coefficient with respect to the substrate. Moreover, it has also been hypothesized that some peculiarities arise from the Van der Waals interaction characterizing Gr and the other 2D materials and also differences in Gr substrate distance . In this context, interfacial defects of SiO 2 , one of the most used dielectrics in electronic devices, were found to be relevant as well as the potentialities to intercalate molecules between Gr and substrate …”

Multi‐Level Electro‐Thermal Switching of Optical Phase‐Change Materials Using Graphene

“…Using Raman spectroscopy characterization, we measured the primary in‐plane vibrational mode, denoted as G peak, at ≈1587 cm −1 and the maximum of the 2D peak of graphene across all devices at ≈2704 cm −1 , which are shown in Figure S1, Supporting Information. We attribute the shift of this peak from the typical to p‐doping from the SiO 2 substrate—especially after alumina deposition at high temperatures [ 58,59 ] —and to compressive strain from the several fabrication steps. With an intensity ratio I 2D / I G of up to 4.21, we verified that our graphene consisted of a single‐layer sheet.…”

“…[ 77 ] The single‐layer graphene was simulated with a chemical potential of 0.2 eV, which was experimentally measured at room temperature [ 64,78 ] and reflected the doping of graphene by the SiO 2 substrate. [ 58 ] In Figure 4b, we plot the calculated real part of the effective refractive index for 30‐nm‐thick GSST covering the entire 800‐nm‐wide waveguide. We observe a change in the real effective refractive index of Δ n eff = 0.28 and Δ n eff = 0.064, at λ = 1550 nm, for the two fundamental modes, transverse electric (TE) and transverse magnetic (TM), respectively.…”