Fig. 2: Modulation of absorption spectra in a Fabry–Pérot (F–P) cavity with MoS2 layers of varying thickness.
a Absorption spectra of MoS2/Au heterostructures with (red) and without (blue) a top layer of ultrathin (~2.3 nm) Au applied via the sputter method (schematic shown in lower inset). Upper right inset shows optical micrograph of the measured sample, with coloured dashed lines indicating the two sectors being analysed. The thickness of the MoS2 is 24 nm, and it was also included in the analysis of (c). b Absorption spectra show a redshift of the NIR absorption peak as the thickness of the MoS2 layer increases. c Absorption peak value (left y-axis) and the center of the peak wavelength (right y-axis) for the same six samples shown in panel (b). Simulation data (red line) were obtained using the transfer matrix method, demonstrating the formation of an F-P-like cavity in the MoS2/Au heterostructure. d Schematic of the absorption process from the midgap state in the hybridized MoS2/Au layer. CBM, VBM and Ef are the abbreviation of conduction band minimum, valence band maximum and fermi level energy respectively. e F-P-like cavity formed in the MoS2/Au heterostructure. Light reflected from the top and bottom interfaces of MoS2 creates destructive interference
