Pulsed-laser-deposited p-type ZnO films with phosphorus doping

Abstract

We report the preparation of p-type ZnO thin films on Al2O3(0001) substrates with phosphorus doping by pulsed laser deposition using Zn3P2 as the dopant source material. The results of the Hall effect measurements taken at room temperature indicate that the 3-mol% phosphorus-doped ZnO films thermally annealed at temperatures between 600 and 800°C under an O2 atmosphere exhibit p-type behavior with a hole concentration of 5.1×1014−1.5×1017cm−3, a hole mobility of 2.38−39.3cm2∕Vs, and a resistivity of 17−330Ωcm. The low-temperature (15K) photoluminescence results reveal that the peak related to the neutral-acceptor bound exciton (A0,X) emission at 3.358eV is only observed in the films showing p-type behavior. Our results not only demonstrate that there is a narrow temperature window for rapid thermal annealing in which phosphorus-doped p-type ZnO films can be obtained, but also suggest that the use of Zn3P2 can provide an effective approach to the preparation of p-type ZnO films.