Microwave Conductivity of Very Thin Graphene and Metal Films

Abstract

The surface resistance of Ag, Au and A1 thin conducting films deposited on low loss dielectric substrates at microwave frequencies using TE011 mode single post-dielectric resonator (10-13.22 GHz) was measured to calculate their conductivity in relation to layers thickness. This method enabling measurements near metal-insulator percolation transition was also applied for epitaxial graphene deposited on semi-insulating SiC. Moreover, effective microwave conductivity has been determined for intentionally made aluminum island structure where the DC conductivity is equal to zero. Special attention was paid to films thickness measurements which is critical for accuracy of sheet resistance calculation. Conductivity of thin metal layers and very thin graphene was compared.

Contact-free sheet resistance determination of large area graphene layers by an open dielectric loaded microwave cavity

“…[14][15][16][17] Krupka et al reported the use of shielded end post dielectric resonators for characterization of ultrathin metal films, including graphene, 18 and discussed the different regimes of conductivity with respect to the resonator response. 19 In our recent contribution, the sheet resistance of a variety of graphene layers on 10 Â 10 mm 2 substrates was determined from the measured quality factor of a closed microwave cavity loaded with a sapphire dielectric puck and the sample under test.…”

Terahertz graphene optics

“…A 13 GHz dielectric resonance oscillator (DRO) measurement (spot frequency) of multilayer graphene on SiC was made by Krupka, but the per layer conductance was not determined [13,14]. An on-chip coplanar waveguide measurement technique was recently employed to study single-layer graphene (SLG) up to 110 GHz [15].…”

Hemispherical and aspheric WGM dielectric resonators with conducting plane: Radiation and conductivity losses in millimeter wavelength range

“…This result is rather unexpected and demands the further studying. Nevertheless, it is useful for developing sensors of the surface impedance of superconductors or other types of conductors, such as graphene, which is important for contactless measurement of conductivity [7].…”