We want to find the equivalent circuit of an optical device (Modulator, absorber), which consists of graphene and dielectric layers. Can anyone suggest me any article, book or method for equivalent circuit calculation?
You have to model each part of your device separately. For instance, for absorber case dielectric is modeled via pure imaginary impedance, The bottom layer (Gold, Silver, or other noble metals) are modeled via short circuit (If the thickness be larger than penetration depth of incident waves). And most important part, graphene can be modeled by RLC branched. The exact equations for some popular graphene patterns such as periodic arrays of ribbons and disks are available.
See:
Article Graphene-based THz absorber: adjustability via multiple gate biasing
Article Multi-Bias Graphene-Based THz Super Absorber
So, you have to specify your graphene pattern to know about equivalent impedance. Or try to extract equivalent impedance by simulators.
Ali Biabanifard
I appreciate your kind answer Sadegh Biabanifard . If we want to embed a semiconductor layer inside a dielectric layer, which is sandwiched between two graphene layers. Is it possible to assume the dielectric layer and the semiconductor layer as parallel capacitors?
Dear Hossein Karimkhani , the graphene can be assumed as a parallel impedance due its ultra thin thickness and point load effects. For your question, if a graphene placed between dielectric and semiconductor layer, YES you are right, you can while the graphene equivalent impedance is placed between these two impedance.
Dear Sadegh Biabanifard , thanks for sharing the information, and your clear explanation.
Dear Sadegh Biabanifard , just one more question. If we make a multilayer structure with the layer order of (1:graphene/2:upper semiconductor/3:metal and air " two metal layers and air are series, and between two metal layer is air"/4:lower semiconductor/5:dielectric/6:graphene), can we assume the upper semiconductor, the lower semiconductor and the air as the parallel capacitors? For example in the attached file (from Article Review of graphene modulators from the low to the high figur...
), which I changed the layers.- Badges
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