Thin films By Ultrasonic Spray Pyrolysis

Thin films By Ultrasonic Spray Pyrolysis. Optical transitions and photoluminescence of fluorine-doped zinc tin oxide thin films prepared by ultrasonic spray pyrolysis

Thin films of fluorine-doped zinc tin oxide were deposited on borosilicate glass by ultrasonic spray pyrolysis. Structural and elemental investigations revealed that all films have a single-phase polycrystalline tetragonal rutile structure and proved the successful incorporation of zinc ions into tin sites and the fluorine ions into the sites of oxygen vacancies. A comprehensive analysis of the optical transitions in fluorine-doped zinc tin oxide films was presented.

All films show high optical transparency (≥85%) in the visible range. Four direct optical transitions were observed in the range 3.8 – 5.1 eV by spectrophotometric measurements, in addition to three transitions identified by photoluminescence. From these transitions observed for the first time in fluorine-doped zinc tin oxide, three states of point defects were determined in the bandgap and attributed to the neutral, singly- and doubly-ionized oxygen vacancies.

The ascription of these states to oxygen vacancies was supported by the x-ray photoelectron spectroscopy measurements. The band diagram of fluorine-doped zinc tin oxide was sketched, demonstrating the observed transitions. The obtained results are expected to have their imprint on understanding the optical processes in fluorine-doped zinc tin oxide and evaluating the future utility of it in various optoelectronic applications.