The grain boundary related p-type conductivity in ZnO films prepared by ultrasonic spray pyrolysis

摘要

Intrinsic p-type ZnO thin film was fabricated on sapphire substrate by ultrasonic spray pyrolysis, the p-type ZnO film is achieved using O_2 as the carrier gas, with a resistivity of 2.18 Ω cm~(-1), a carrier concentration of 1.10×10~(16) cm~(-3), and a high Hall mobility of 261 cm~2/Vs. The scanning capacitance microscopy images and annealing the p-type ZnO indicate that the absorbed oxygen in the grain boundary (GB) aroused the p-type conductivity, and the high Hall mobility of the p-type ZnO film own to the quasi-two-dimensional hole gas, which was induced by the negatively charged interface states in the GBs.