DFT study of NO2 adsorption on the AlN nanocones

Using density functional theory, the adsorption of NO2 molecule on an AlN nanocone is investigated in terms of energetic, structural, electronic and field emission properties. The NO2 is preferentially chemisorbed on the pentagon of the cone apex, releasing energy of 65.43 kcal/mol. The AlNC is transformed from an intrinsic semiconductor with Eg of 2.86 eV to extrinsic p-type one with smaller Eg of 1.62–2.34 eV upon adsorption processes. The largest reduction of Eg is predicted when the NO2 molecule is adsorbed on a hexagonal ring of the AlNC containing homonuclear N–N bonds. We conclude that the AlNC may transform the presence of the NO2 molecule into an electrical signal. The emitted electron current density from the AlNC surface may be also decreased in the presence of NO2 molecules. We also found that the electronic sensitivity of AlNC to NO2 molecule may be tuneable in the presence of an external electric field.