Effect of annealing temperature and ambient gas on phosphorus doped p-type ZnO

The authors report on the thermal activation of phosphorus doped p-type ZnO thin films grown by radio frequency magnetron sputtering. The p-type ZnO was produced by activating phosphorus doped ZnO thin films in N-2, Ar, or O-2 ambients. The hole concentration of the p-type ZnO, prepared in an O-2 ambient, showed a lower hole concentration compared to samples annealed in N-2 and Ar ambients. The activation energies of the phosphorus dopant in the p-type ZnO under different ambient gases indicate that phosphorus atoms replace oxygen atoms in the ZnO to form P-O which acts as an acceptor. (c) 2007 American Institute of Physics.