Gas Concentration Effect on Channel Capacitance in Graphene Based Sensors

Graphene, a superior material, with two-dimensional (2D) monolayer honeycomb structure of carbon, is of significant importance topic in the all fields specially chemistry, physics, biology, electronic and nanotechnology. Caused by its exclusive properties including high conductivity, suitable in biological applications and high surface area, high mechanical strength, is the most remarkable and encouraging materials for a large number of theoretical studies. Sensors are of the essential parts of the production technology. Investigations about sensors show that for faster response time, higher accuracy and increased sensitivity it needs to be improved. At the present time, carbonbased materials as a bright future substance are noteworthy in the sensing technology. Through the extraordinary high surface region and individual characteristic of graphene any molecular disturbance can be easily analyzed, and gas sensor based on graphene can be assumed to have extremely sensitivity for detection of gas molecules. In this paper an analytical model of CO2 gas sensor based on graphene conductance variation is presented. Capacitance gradient which made up among the channel and gate as an important property of FET device is employed in our interpretation. Gas concentration and its effect on Capacitance as a modeling platform are recommended. Finally the comparison study between model and experimental data is analyzed.