Fig. 2: Characterization of transferred CVD graphene and graphene/hexagonal boron nitride (hBN) heterostructures.
From: Large-area integration of two-dimensional materials and their heterostructures by wafer bonding
a Photograph of a 100-mm-diameter silicon wafer with van der Pauw (vdP) devices. The graphene sheet covers the entire wafer and lies on top of multilayer CVD hBN in the marked region. b Extracted sheet resistance (Rsh), carrier density (n), and charge carrier mobility (μ) from Hall measurements of vdP devices at room temperature (number of devices: 18 graphene (blue); 9 graphene/hBN (red)). c Spatially resolved map of Rsh extracted from noncontact terahertz near-field spectroscopy, indicating a uniform coverage of graphene on the entire high resistive silicon wafer (average within the marked region: \(450 \pm 50\,{\Omega}\,{\mathrm{sq}^{-1}}\)). d Correlation map of the Raman G and 2D peak position (ωG and ω2D, respectively) of the transferred graphene (triangles) and the graphene/hBN heterostructure (circles). The colormap represents the extracted full-width at half-maximum of the 2D peak (Γ2D) of the transferred graphene (Γ2D,gr) and the graphene/hBN heterostructure (Γ2D,gr/hBN). The open circle indicates the peak positions of intrinsic graphene74. The total number of spectra for graphene on bisbenzocyclobutene (BCB) and graphene on hBN is 430 and 124, respectively. Note, a, b are from the same sample, whereas c, d are performed on a second sample.
