▎ 摘　　要

Graphene, a 2-dimensional monolayer form of sp(2)-hybridizated carbon atoms, is attracting increasing attention due to its unique and superior physicochemical properties. Covalently functionalized graphene layers, with their modifiable chemical functionality and useful electrical properties, are excellent candidates for a broad range of sensors, suitable for biomedical, optoelectronic, and environmental applications. Here, we present extensive study of transport properties of sensors based on covalently functionalized graphene monolayer (GML) with graphene electrodes. The transmissions, density of states, and current voltage characteristics supported by analysis of charge distribution of GML functionalized by -CH3, -CH2, -NH2, -NH, and -OH fragments have been calculated by means of density functional theory (DFT) and nonequilibrium Green's function (NEGF). Further, we demonstrate how to control the device sensitivity by manipulating (i) concentration, (ii) particular arrangement, and (iii) type of surface groups. We explain the underlying detection physical mechanisms. Comparisons of the theoretical results to available experimental data are provided and show good agreement.