The effect of atmospheric doping on pressure-dependent Raman scattering in supported graphene

Abstract

Atmospheric doping of supported graphene was investigated by Raman scattering under different pressures. Various Raman spectra parameters were found to depend on the pressure and the substrate material. The results are interpreted in terms of atmospheric adsorption leading to a change in graphene charge carrier density and the effect of the substrate on the electronic and phonon properties of graphene. It was found that adsorption of molecules from the atmosphere onto graphene doped with nitrogen (electron doping) compensates for the electron charge. Furthermore, the atmosphere-induced doping drastically decreases the spatial heterogeneity of charge carriers in graphene doped with nitrogen, while the opposite effect was observed for undoped samples. The results of this study should be taken into account for the development of sensors and nanoelectronic devices based on graphene.

Adsorption dynamics of CVD graphene investigated by a contactless microwave method

“…The G/2D peak intensity histogram (figure 4d) ,in conjunction with the 2D histogram of figure 4c, clearly shows a continuous distribution, where the average G/2D peak intensity ratio is slightly less than 0.5. This is attributed to the sample being slightly p-doped as charge doping is known to enhance (decrease) the G (2D) peak intensity such that the G/2D peak is still indicative of monolayer graphene [72,73]. Similarly, the Figure 4: Surface characterisation of CVD graphene wet transferred onto a silicon substrate.…”

Catalyst-Less and Transfer-Less Synthesis of Graphene on Si(100) Using Direct Microwave Plasma Enhanced Chemical Vapor Deposition and Protective Enclosures

“…Possible sources of such behavior would be adsorbates or substrate-induced effects. Atmospheric adsorbates (oxygen, water) usually result in p-type doping of the graphene [ 59 , 60 , 61 ]. P-type self-doping for graphene transferred onto the SiO 2 substrate occurred due to various surface treatments and residual charges created on the substrate [ 62 ].…”

Graphene‐SiO2 Interaction from Composites to Doping

“…In this context, different doping strategies have been highlighted starting from chemical doping during Gr production, after production thermal doping, irradiation induced doping, and adsorption induced doping . A relevant role of the substrate in the doping effect has been guessed and it has been suggested that free standing Gr is subject to minor efficiency of doping as compared to Gr opportunely supported . Furthermore, in many cases it has been evidenced a critical role of Gr‐substrate interaction in tuning the former properties, as well as some criticisms linked to the temperature applied for processing or during the use of devices that can damage the Gr itself .…”