High-pressure Raman spectroscopy of graphene

Abstract

In-situ high pressure Raman spectroscopy is used to study monolayer, bilayer and few-layer graphene samples supported on silicon in a diamond anvil cell to 3.5 GPa. The results show that monolayer graphene adheres to the silicon substrate under compressive stress. A clear trend in this behaviour as a function of graphene sample thickness is observed. We also study unsupported graphene samples in a diamond anvil cell to 8 GPa, and show that the properties of graphene under compression are intrinsically similar to graphite. Our results demonstrate the differing effects of uniaxial and biaxial strain on the electronic bandstructure. ArticleThe discovery of graphene in 2004 [1] has led to many advances in solid state physics. Research into this new material is fuelled by interest in fundamental physics as the quantum Hall effect has been observed in graphene at room temperature [2] and electrons within graphene behave as massless dirac fermions, mimicking relativistic particles [3]. Graphene has been suggested as a candidate for a wide variety of applications in electronics (due to its ballistic transport at room temperature) and composite materials [2]. It is the first experimental realisation of a truly 2-dimensional material.To date there have been no studies published on graphene at high pressure. This is surprising in view of the huge interest in the mechanical properties of graphene [4-9] motivated particularly by its possible applications in nanoelectronics [4,5]. Strain monitoring is of critical importance [10,11] in this field. It should be of particular relevance in the case of graphene due to the predicted dependence of electronic bandgap on strain [12], and also due to the fact that some of the materials related to graphene are intrinsically stressed due to the presence of the substrate, for example graphene grown epitaxially on SiC [13]. The possibility of using graphene as an ultrasensitive strain sensor has also been suggested [9]. Study of graphene at high

Pressure-induced semiconducting to metallic transition in multilayered molybdenum disulphide

“…The DAC technique coupled with a hydrostatic pressure medium (Fig. 1b) has been shown to be effective in elucidating the electrical, vibrational, optical and structural properties of a plethora of materials 21,[23][24][25] . The optically transparent window of the diamond allows us to conduct a series of in situ highpressure experiments including accurate pressure calibration from ruby fluorescence, electrical transport measurements and optical Raman and synchrotron X-ray diffraction (XRD) spectroscopy 26 , leading to the observation of S-M transition in multilayered MoS 2 at high pressures.…”

Raman Spectroscopy Study of Graphene Under High Pressure

“…Raman G peak shift slope is decreasing as the pressure is increased a trend which has been observed in other publications as well. [5] The FWHM shows a considerable broadening for 2D peak after plasma treatment which also has been observed by Nourbakhsh et al (2010). as the Raman spectroscopy of nontreated one.…”

“…To date, except for Proctor et al (2009), there are no studies published on graphene at high pressures and this is surprising considering the growing interest in the mechanical properties of graphene and its possible application in nano electronics. Taking into account the predicted dependence of electronic band gap on strain, it is very important to apply strain and monitor strain.…”

“…Taking into account the predicted dependence of electronic band gap on strain, it is very important to apply strain and monitor strain. Since Raman spectrum allows unambiguous, highthroughput, nondestructive identification of graphene layers [5] , study of graphene at high pressure combined with Raman spectroscopy has the potential to develop into an important component in the characterization and understanding of this remarkable new material. Also it has been shown that the electronic structure of graphene indicated by its…”

“…Red line plotted using the data collected in the current research, compared to data presented in other studies. [5] The points gathered using zirconia anvils seem to be scattered. The pressure limits reached using zirconia anvils are around 2GPa.…”