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

Abstract

Intrinsic p-type ZnO thin film was fabricated on sapphire substrate by ultrasonic spray pyrolysis, the p-type ZnO film is achieved using O2 as the carrier gas, with a resistivity of 2.18 Ω cm−1, a carrier concentration of 1.10×1016 cm−3, and a high Hall mobility of 261 cm2/V s. 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.