Probing number of layers and quality assessment of mechanically exfoliated graphene via Raman fingerprint

To attain the expected outcomes of any measurement, probing the quality of graphene is a prerequisite among the various graphene samples. Herein, we investigate the identification of the number of layers in mechanically exfoliated graphene using Raman spectroscopy. The intensity ratio (I-2D/I-G) and peak width of the 2D peak have been used to distinguish the number of layers. The 2D peak consists of a single Lorentzian fit having peak width 24 cm(-1) in single layer graphene (SLG) and splits into four, six and five components for bilayer, trilayer, and five layers respectively. Further, the quality of graphene has been analyzed by I-2D/I-G, Raman mapping and the charge carrier mobility. In addition, the high quality of graphene has been encapsulated in terms of two phonon scattering processes and the variation in I-2D/I-G of SLG as a result of crossover from electron-electron to electron-hole scattering. The maximum mobility of SLG has been obtained similar to 11,931 cm(2)V(-1)s(-1) when the peak width and I-2D/I-G are 23.88 cm(-1) and 5.36 respectively. Hence, the present study sets a platform to use Raman scattering as a probe for quantification of graphene layers and Raman mapping with spatial resolution provides the solution for specific area selection to fabricate the next generation graphene based quantum devices.