P-doped p-type ZnO films deposited on Si substrate by radio-frequency magnetron sputtering

Abstract

P-doped ZnO films were deposited on n-Si substrate by radio-frequency magnetron sputtering. Hall measurements revealed that the films annealed in situ at 750°C in an oxygen ambient at a pressure of 1.3×10−3–3.9×10−3Pa showed p-type behavior with a hole concentration of 2.7×1016–2.2×1017cm−3, a mobility of 4–13cm2∕Vs, and a resistivity of 10.4–19.3Ωcm. Films annealed at 750°C in a vacuum or in oxygen ambient at higher pressures (5.2×10−3 and 6.5×10−3Pa) showed n-type behavior. Additionally, the p-ZnO∕n-Si heterojunction showed a diodelike I-V characteristic. Our results indicate that P-doped p-type ZnO films can be obtained by annealing in oxygen ambient at very low pressures.