Theoretical Calculation Of Graphene Sensing Performance

Graphene has a good conductivity thermal conductivity characteristics and unique zero band gapcharacteristics, which makes it as a gas sensor is a good choice. The laboratory has confirmed the graphene as a gas sensor may, but the lack of theoretical basis and guidance, made in the laboratoryto try and repeat the main means to improve the performance of all aspects of the graphene. In order to improve the preparation of graphene technology, for the laboratory preparation of graphene are explained theoretically and guide, theoretical calculation method of the use of graphene.DFT based on density functional theory, using the first principles calculation software vasp modeling for the graphene is calculated, through the construction of theoretical simulation and calculation of graphene and related electronic structure properties of graphene is studied, the feasibility of graphene as a gas sensor gives explanation and guidance. Handling of graphene including the choice of different layer contrast research its electronic structure properties, the adsorption gas after the electronic structure of graphene properties, selection of gas to hydrogen, oxygen and nitric oxide. Doping of graphene research, chooses the dopant atoms for B and N, contrast before and after doping is studied the electronic structure of graphene, and the different layers of graphene after doping electronic structure properties of adsorbed gas. Research structure shows that the different layers of graphene on the gas sensing properties have a certain degree of similarity, as a gas sensor can be as a substitute each other. Also points out the advantages and disadvantages of them, the lower the number of high sensitivity and stable but not the number of high stability is good but the sensitivity of slightly. At the same time, the study found that doping or adsorption will affect the electronic structure of graphene, the from microscopic degree, adjusting the energy level structure of graphene has important significance. Graphene doped after its zero band gap will be destroyed, the characteristics of band will be away as semiconductor, makes the conductivity of graphene is affected. Doping also affects the stability of the graphene, cause the overall energy change.