Fig. 2
From: Observing of the super-Planckian near-field thermal radiation between graphene sheets
Characterization of i-Si/Gr properties. a A typical 3D AFM picture of the i-Si/Gr sample. The largest roughness of the sample is about 50 nm. b The Raman spectrum of the i-Si/Gr sample. The monolayer feature of graphene is identified by the strong 2D resonance peak. c The absorption spectrum of graphene on intrinsic silicon. The red dots are measured results by FTIR and the blue line is a Gaussian function fitting. TGr and TSi denote the transmittance with and without the graphene cover, respectively. The “2EF onset” of the inter-band transition is estimated at about 4832.8 cm−1, corresponding a Fermi level at EF = 0.27 eV. d Measured (dashed lines) and calculated (solid lines) FTIR spectra at three different target gap sizes of 3.7, 1.4, and 0.43 μm. The uncertainty of gap size is considered here so that the calculated lines (red and blue) could cover the experimental curves measured at various spatial points. The statistic value for the smallest gap we designed is about 430 ± 25 nm. e Correspondence between the measured and the target gap sizes. The gap uncertainty is shown by the error bar derived from the measurements at multiple points. The black curve is a guidance line for eye, which shows nearly a linear relationship when the gap value is within few micron meters. Figure 2 by Yang J et al.
