Role of n-type codopants on enhancing p-type dopants incorporation in p-type codoped ZnSe

摘要

We propose materials design for the fabrication of low-resistivity p-type ZnSe crystals using a new doping method which involves simulataneous codoping of both n- and p-type dopants, based on the ab initio electronic band structur calculations. We have clarified that while doping of acceptor dopants, Li_(Zn) and N_(Se), leads to the detabilization of the ionic charge distributions in p-type ZnSe crystals, doping of donor dopants, In_(Zn), Cl_(Se) or I_(Se) gives rise to n-type doped ZnSe with high donor concentration due to a large decrease in the Madelung energy. The codoping of the n- and p-type dopants (the ratio of their concentrations is 1:2) enhances the incorporation of the acceptors in p-type ZnSe crystals due to a decrease in the Madelung energy, resulting in the formation of the p-n-p complexes which occupy nearest-neighbor sites. It results in an increase in the net carrier densities and the hole mobility due to a change in the scattering mechanism from that caused by long-range Coulomb scatters to that by short-range dipole-like ones.