Field emission properties of Ge-doped GaN nanowires

The field emission properties of Ge-dopted GaN nanowires have been investigated in theory and experiment. Ge-doping affecting field emission properties of GaN nanowires has been calculated via the basis of density functional theory (DFT). The results indicate that Ge-doped GaN nanowires have a minimum work function value of 2.37 eV when the impurity concentration is about 4.2 at.%, which is superior for application in cathode material for field emission. In addition, Ge-doped GaN nanowires have been synthesized via CVD method in our experiment. The results indicate: (1) the structure of GaN NWs is wurtzite hexagonal and the growth direction is along [0001]. (2) Ge-doped GaN nanowires possess a lower turn-on field than the pure GaN nanowires, which means Ge-doping can enhance the field emission properties of GaN nanowires, and this is consistent with the theoretical calculation results.