Study on anomalous n-type conduction of P-doped ZnO using P2O5 dopant source

Abstract

The unexpected n-type conduction observed in P-doped ZnO thin films fabricated from rf magnetron sputtering, was studied systematically through a combined approach of experiment and computer modeling. The carrier stability was predicted from first-principles density functional theory and chemical thermodynamic calculations. It demonstrated that, under oxygen-poor growth condition and low temperature, the stable doping defect PO−1 may have negative effect on n-type conduction and, under oxygen-poor growth condition and high temperature, the stable doping defect may contribute significantly to the n-type conduction. Furthermore, under oxygen-rich growth condition, the stable doping defect PZn1 may help to maintain the n-type conduction at high oxygen partial pressures. Our model predictions are in good agreement with experimental observations in anomalous conduction of P2O5-doped ZnO thin films and provide scientific explanation. This research not only revealed increased fundamental understanding on electronic behaviors but also provided a fabrication strategy for P-doped n-type ZnO.