Fermi Level Of Graphene Layer Research Articles

Dual-band tunable perfect metamaterial absorber in the THz range.

In this paper, a dual-band perfect absorber, composed of a periodically patterned elliptical nanodisk graphene structure and a metal ground plane spaced by a thin SiO(2) dielectric layer, is proposed and investigated. Numerical results reveal that the absorption spectrum of the graphene-based structure displays two perfect absorption peaks in the terahertz band, corresponding to the absorption value of 99% at 35μm and 97%at 59μm, respectively. And the resonance frequency of the absorber can be tunned by controlling the Fermi level of graphene layer. Further more, it is insensitive to the polarization and remains very high over a wide angular range of incidence around ±60(0). Compared with the previous graphene dual-band perfect absorption, our absorber only has one shape which can greatly simplify the manufacturing process.

Investigation of graphene assisted tunable terahertz metamaterials absorber

By using the graphene-SiO2-Si-dielectrics-metallic ground plane (GSiO2SiDM) structures, we investigate the tunable properties of graphene metamaterials (MMs) absorbers in the terahertz region, including the effects of operation frequency, Fermi level, and graphene structure patterns. The results manifest that the graphene tunable GSiO2SiDM structure can achieve net absorption by changing structure parameters and the Fermi level of graphene layer. The resonant absorption and reflection curves of the GSiO2SiDM structures can be shifted in a wide range via controlling the applied electric fields. The modulation depth of resonant amplitude and frequency can reach more than 60% and 30%, respectively. The resonant peak (dip) of the absorption (reflection) curves shift to high frequency with the increase of Fermi level of the graphene layer. Due to broad absorption curve, the graphene MMs absorbers structures are suitable for the fabrication of broad absorber. The results are very useful to design novel devices, such as thermal detectors, imager, and biosensors.

Graphene-supported tunable near-IR metamaterials.

By integrating the metallic metamaterials (MMs) with a graphene layer, the resonant properties of an active tunable device based on the metal-SiO(2)-graphene (MSiO(2)G) structure have been theoretically investigated in the near-IR spectral region. The results manifest that the influences of the graphene layer on the propagation properties are significant. Owing to the tunability of the Fermi level of graphene, the resonance of transmitted or reflected curves can be tuned in a wide range (160-193 THz). To an original metal unit cell structure, an elevated Fermi level of graphene layer enhances the resonance dips and shifts it to the higher frequency. Compared with the original structure, the corresponding complementary MMs structure shows a much sharper spectral curve and can be used to fabricate a switcher or filters. The results are very helpful for designing graphene plasmonic devices.