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

Abstract

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.