Realization of p-type ZnO thin films via phosphorus doping and thermal activation of the dopant

A p-type ZnO was prepared on a sapphire substrate using P2O5 as a phosphorus dopant. As-grown n-type ZnO films doped with phosphorus showed electron concentrations of 10(16) - 10(17)/ cm(3) and these films were converted to p-type ZnO by a thermal annealing process at a temperature above 800 degreesC under a N-2 ambient. The electrical properties of the p-type ZnO showed a hole concentration of 1.0x10(17) - 1.7x10(19)/cm(3), a mobility of 0.53 - 3.51 cm(2)/Vs, and a low resistivity of 0.59 - 4.4 Omega cm. The phosphorus-doped ZnO thin films showed a strong photoluminescence peak at 3.35 eV at 10 K, which is closely related to neutral acceptor bound excitons of the p-type ZnO. This thermal activation process was very reproducible and effective in producing phosphorus- doped p-type ZnO thin films, and the produced p-type ZnO was very stable. (C) 2003 American Institute of Physics.