Dopant Sources Choice for Formation of p-Type ZnO: Phosphorus Compound Sources

Abstract

Fabrication of p-type ZnO has proven difficult and usually inconsistent despite numerous worldwide efforts. In this theoretical study we explored the problem of p-type ZnO formation using both DFT and thermochemistry calculations. Our DFT models predicted that Zn3P2 is a good dopant because it can lead to a shallow acceptor level at 0 K. Additional thermochemistry calculations demonstrated that this shallow acceptor can be further stabilized in a real fabrication process. Our models explain well the observed trends for both n- and p-type phosphorus-doped ZnO and especially the observed inconsistent behaviors of P2O5 dopant. A new strategy of fabricating p-type ZnO was proposed thereafter. This research may also help to address the problem of dopant selection in the fabrication of other wide-gap semiconductors.