Effects of Nitrogen Partial Pressure Ratio and Anneal Temperature on the Properties of Al–N Co-Doped ZnO Thin Films

The authors report the conversion of conduction type from n-type to p-type in the Al–N co-doped ZnO thin films by using thermal annealing treatment under argon atmosphere. The samples were deposited on fused silica by radio frequency magnetron sputtering. X-ray diffraction measurements showed that ZnO thin films have (002)-preferred orientation and the lattice constant decreases with the increase of nitrogen partial pressure. The average optical transmittance of these films is over 80%. The hole density is around 1.58 × 10¹⁷ cm⁻³ with an annealing temperature of 700°C. After exposing the samples in air for 1 year, the conduction type remains p-type with only a slight decrease of hole density, which indicates that the p-type ZnO with Al–N co-dopants has good electrical stability.