▎ 摘　　要

Defects are often symbolized as deformity in material that deteriorate its performance. However, in nanoscale regime, defects lead to generate a useful and novel material for device applications. In the present report, the vacancy defects, i.e., single vacancy and double vacancy defects (with different symmetry) on graphene sheet have been analyzed to understand the electronic as well as transport properties using density functional theory and NEGF approach. Conductance, current- voltage, and sensitivity analysis of these defected graphene sheets have been examined for its suitability for gas sensing application particularly for ammonia gas. The study observes that a single vacancy defected graphene is a good candidate for ammonia molecule sensing in comparison to double vacancy.