For decades it was thought that two-dimensional crystals were not possible, until the successful preparation of monolayer graphene with mechanical exfoliation proved that two-dimensional planar crystal structures could be isolated. These layers are not only stable but also exhibit remarkable physical and chemical properties not found in their parent materials. For example, the thermal conductivity of suspended monolayer graphene is as high as 5,000 W/mK as measured by Raman spectroscopy, a value much higher than that of bulk diamond or graphite. Similarly, at room temperature, the carrier mobility in graphene can also reach much higher values of up to 15,000 cm 2 V -1 s -1 and is less dependent on temperature than in its bulk counterpart. Because of these outstanding properties, graphene can be used in high-speed electronics, optical devices, chemical sensors, energy production and storage, and DNA sequencing among many other fields.