▎ 摘　　要

Graphene is a single-atom thin layer with sp(2) hybridized and two-dimensional (2D) honeycomb structure of carbon. Because of its exclusive properties including high conductivity, high surface area and high mechanical strength, graphene has attracted a great deal of attention of many researchers in chemistry, physics, biology, nanoelectronics and nanotechnology in the recent years. Due to the fact that different kinds of nanoscale sensors including gas sensors and biosensors are playing important roles in human life, the idea of using promising materials such as graphene to achieve accuracy and higher speed in these devices is becoming a matter of attention. Although there are plenty of experimental studies in this field, the lack of analytical models is felt deeply. To start with modelling, the field effect transistor (FET)-based structure is employed as a platform and graphene conductivity has been studied under the impacts induces by the adsorption of different values of gas concentration on its surface. The reaction between graphene and gas makes new carriers in graphene which cause changes in the carrier concentration and consequently alters the conductance. In the presence of gas, electrons are donated to or withdrawn from the FET channel and this phenomenon is employed as a sensing mechanism. The I-V characteristic of bilayer graphene (BLG) has been incorporated as a measure to study the effects of gas adsorption. In order to assess the accuracy of the proposed models, the obtained results are compared with the existing experimental data and acceptable agreement is reported.