Modelling of Phosphorus and Gallium doped Nano-GNRFET based gas sensor

The modelling of a top-gated and bottom-gated Graphene-based Nano Ribbon Field Effect transistor (GNRFET) for sensing of N₂O and O₂ gases is performed using Sentaurus TCAD and VASP by diffusing the gases over the surface of the Graphene Nano Ribbon (GNR) layer. The Sentaurus model corresponds to that of a doped GNR placed over the gate separated by a thin layer of insulator. From a VASP modelling of a zigzag GNR (ZGNR) doped with Gallium and Phosphorus, it has been observed that the density of states function varies in the presence of the gas. Results of the TCAD analysis also indicate that the gas absorbance by the doped GNR layer is reflected by a sizeable change in the conductivity and drain current making these structures promising candidates for enhanced nano scale sensing of such gases. The size of the Graphene nano ribbon is 90nm × 500nm for the top gated and 350nm × 1um for the bottom gated GNRFET, which has been considered adequate for gas adsorption.