First-principles insights on the electronic and field emission properties of Ga and Al doped germanium nanocones

Density functional theory (DFT) simulations have been performed to study the field emission characteristics of pristine, Ga, and Al substituted germanium nanocone (Ge-NC). The influence due to the substitution of group-III elements on Ge-NC is studied using the density of states (DOS) spectrum and electron density. As a matter of fact, from the molecular electrostatic potential surface, it is noticed that the impurity substitution at the apex of Ge-NC leads to increase in the field emission properties due to delocalization of electron by the charge transfer at the apex of nanocone. In addition, the Mulliken charge transfer, work function and current density of the emitted electron were calculated for the pristine and Ga and Al-doped Ge-NC. The results suggest that the substitution of group-III impurity along the apex of Ge-NC leads to the improved field emission, which can be used for the assembly of vacuum electronics and nanoelectronics.