Alternative sources of p-type conduction in acceptor-doped ZnO

We report first-principles calculations and interface simulations for Zn3P2, a compound that may form during doping of ZnO with phosphorous. While P is a deep acceptor in ZnO and thus unable to produce p-type conductivity, we show that hole accumulation can occur at ZnO/Zn3P2 interfaces due to the unusual valence-band alignment between the two materials. This provides an explanation for the hole conductivity that has been observed in Hall measurements on phosphorous-doped ZnO. (C) 2010 American Institute of Physics. [doi:10.1063/1.3481069]