Physical characterization of ZnO precursors

Abstract

Zinc oxide (ZnO) is an important semiconductor material with multiple applications in piezo-electric transducers, spin functional devices and gas sensors, for instance. In this article, we study optical and structural properties of ZnO thin films obtained from 4 precursors deposited by sol-gel on glass substrates and heated to 4 different temperatures each one. The absorption coefficient and energy band gap were determined from UV-visible absorption spectrum (200 – 1100 nm). The luminescence properties were evaluated from photoluminescence spectrum (350 – 850 nm). The amount of impurities in the final material were obtained from elemental analysis. The energy band gap was found to vary between 3.00 – 3.25 eV, depending on the precursor and the annealing temperature. We discuss and relate the different processes with the impurities and structure of the samples. SEM images of the thin films were added to complete the study