Study of the electronic transport performance of ZnO-SiO2 film: the construction of grain boundary barrier

Purpose

The purpose of this study is to adjust the electronic transport performance of zinc oxide–silicon dioxide (ZnO-SiO₂) film by the construction of a grain boundary barrier.

Design/methodology/approach

ZnO-SiO₂ thin films were prepared on glass substrates by a simple sol-gel method. The crystal structure of ZnO and ZnO-SiO₂ powders were tested by X-ray diffraction with copper (Cu) Kα radiation. The absorption spectra of ZnO and ZnO-SiO₂ films were recorded by a ultraviolet-visible spectrophotometer. The micro electrical transport performance of ZnO-SiO₂ thin films were investigated by conductive atomic force microscope and electrostatic force microscope.

Findings

The results show that the current of ZnO-SiO₂ film decrease, indicating that the mobility of ZnO-SiO₂ film is greatly decreased, owing to the formation of the grain boundary barrier between ZnO and SiO₂. The phase variation of ZnO-SiO₂ film increases due to the electron accumulation at grain boundaries.

Originality/value

ZnO and ZnO-5SiO₂ thin films prepared on glass substrates by a simple sol-gel method were first studied by CAFM and EFM. The band gaps of ZnO and ZnO-5SiO₂ is ∼3.05 eV and 3.15 eV, respectively. The barrier height of ZnO-5SiO₂ film increased by ∼0.015 eV after introducing SiO₂. The phase variation intensity increased to a certain extent after doping SiO₂, due to the increased GB barrier. ZnO-5SiO₂ film will be a promising ETL candidate in the application of QLEDs field.