First-principles calculation ofp-type doping of ZnSe using nitrogen

Abstract

We have employed first-principles density-functional calculations to describe the behavior of nitrogen as a p-type dopant in ZnSe. Our previous finding that the nitrogen acceptor decays by migrating from a substitutional site to a neighboring interstitial site, is described in further detail. In particular the mechanism that accounts for the superior stability of the decayed acceptor is described. We also examine the diffusion of the point defects that result from the decay of the acceptor, which have been found to be responsible for the degradation of ZnSe-based devices. Furthermore we pay attention to the behavior of a ${\mathrm{N}}_{2}$ molecule within the ZnSe matrix, and to alternative doping strategies that utilize codoping with Cl or In. While the introduction of Cl does not remove the instability of the nitrogen acceptor, codoping with In may provide a means to prevent the degradation of the dopant. We conclude by presenting similar simulations for ZnTe that show the absence of the aforementioned decay mechanism, and refer to experimental results from a ZnTe based diode.