The role of quantum confinement in p-type doped indium phosphide nanowires

The impurity state responsible for current flow in zinc-doped indium phosphide nanowires is characterized through first-principles calculations based on a real-space implementation of density functional theory and pseudopotentials. The binding energy of the acceptor state is predicted to range from the value of the acceptor state in the bulk up to values of similar to 0.2 eV in the thinner nanowires as a result of the two-dimensional quantum confinement. The location of the impurity atom within the nanomaterial is not found to play a prominent role in determining the characteristic properties of the state. Our results show that, in thin nanowires, quantum confinement can move the defect level deep into the energy gap.