Biaxial Strain Transfer in Supported Graphene

Abstract

Understanding the mechanism and limits of strain transfer between supported 2D systems and their substrate is a most needed step toward the development of strain engineering at the nanoscale. This includes applications in straintronics, nanoelectromechanical devices, or new nanocomposites. Here, we have studied the limits of biaxial compressive strain transfer among SiO, diamond, and sapphire substrates and graphene. Using high pressure-which allows maximizing the adhesion between graphene and the substrate on which it is deposited-we show that the relevant parameter governing the graphene mechanical response is not the applied pressure but rather the strain that is transmitted from the substrate. Under these experimental conditions, we also show the existence of a critical biaxial stress beyond which strain transfer become partial and introduce a parameter, α, to characterize strain transfer efficiency. The critical stress and α appear to be dependent on the nature of the substrate. Under ideal biaxial strain transfer conditions, the phonon Raman G-band dependence with strain appears to be linear with a slope of -60 ± 3 cm/% down to biaxial strains of -0.9%. This evolution appears to be general for both biaxial compression and tension for different experimental setups, at least in the biaxial strain range -0.9% < ε < 1.8%, thus providing a criterion to validate total biaxial strain transfer hypotheses. These results invite us to cast a new look at mechanical strain experiments on deposited graphene as well as to other 2D layered materials.

Raman study of graphene nanoribbon analogs confined in single‐walled carbon nanotubes and their high‐pressure transformations

“…Above 6 GPa, the Raman peak at 1362 cm −1 shows a linear up‐shift of 4.5 cm −1 /GPa with increasing pressure. This pressure coefficient is close to the ones of graphene supported on diamond or of graphite itself. As shown in previous work, the response of graphene samples supported on different substrates under high pressure is different because of the substrate–graphene interaction.…”

“…This pressure coefficient is close to the ones of graphene supported on diamond or of graphite itself. As shown in previous work, the response of graphene samples supported on different substrates under high pressure is different because of the substrate–graphene interaction. The reported pressure dependences of the G‐band wavenumber for graphite vary ranging from 4.1 to 4.7 cm −1 /GPa.…”

Size‐controlled graphene‐based materials prepared by annealing of pitch‐based cokes: G band phonon line broadening effects due to high pressure, crystallite size, and merging with D′ band

“…No significant medium effect is expected, as the samples are composed of grains of several micrometers. If we compare this value with recent findings in graphene, taking care to consider medium and substrate effects, a similar value is found. The linewidth increases significantly with increasing pressure for pressure higher than 8 GPa.…”

“…Initially, it remains constant up to 9 GPa and then increases abruptly at higher pressure. This takes place irrespective of the type pressure transmitting medium (or even no medium) . So far, no high‐pressure Raman measurements have been reported in literature for a series of samples with controlled degrees of graphitization and the controlled particle size.…”

Temperature dependence of the double‐resonance Raman bands in monolayer MoS2

“…Considering the linear thermal expansion coefficient of 0.56 × 10 −6 K −1 for fused quartz and of 4.76 × 10 −6 K −1 for MoS 2 , the cooling down process from 300 to 80 K would induce a strain of ~0.1% in MoS 2 , considering the perfect adhesion with the substrate. However, as shown in previous works of graphene and MoS 2 on SiO 2 /Si, the strain transfer is usually partial and the adhesion depends on the type of the substrate, being very weak for SiO 2 .…”