Doping of acceptor impurities into ZnO

Fabrication of p-type ZnO is a recent issue. Elements of I and V column are used as p-type dopant of ZnO. Nitrogen (N) is considered as proper p-type dopant of ZnO. When N is substitute for O, the estimated covalent length between Zn and N is 0.201 nm, which is nearly close to the length of Zn-O (0.197 nm) compared with other p-type dopants of Zn-P (0.248 nm) and Zn-As (0.256 nm). This small difference in covalent length reduces the strain in ZnO lattice from doping. However, N-doped ZnO showed high resistive n-type conductivity, even though N-doping concentration was above /spl sim/E20/cm/sup 3/. The alternative for p-type dopant is Li/sub 3/N. In this case, both elements of Li and N are useful for p-type dopant in ZnO. We report a systematic study of N and Li/sub 3/N doped ZnO layers. N and Li incorporation are confirmed by SIMS. Incorporation of N and Li into ZnO layers greatly influences structural and optical properties of ZnO layers.