Modification of the Physical Properties of SnO2 Thin Films for Optoelectronic Applications Combining Rapid Atmospheric Pressure Chemical Vapor Deposition Technique and Heat Treatment

Abstract

Herein, the influence of the postannealing process on tin oxide thin films deposited by chemical vapor deposition in the atmospheric pressure technique is investigated. The as‐deposited films are heat treated under different environments, including ambient air, oxygen, nitrogen, and vacuum. The postannealing process is performed at 600 ºC for 60 min. It is worth mentioning that no sign of damage or destruction has been observed in samples after the annealing process. The structural characterization of the thin films is studied using X‐ray diffraction analysis, which reveals an increase in the peak intensities after annealing. Field‐emission scanning electron microscope surface morphology shows that heat‐treated tin oxide thin films have larger grain sizes than as‐deposited ones. Hall effect analysis shows a significant reduction in sheet resistance and a substantial increase in mobility after postannealing. The ultraviolet–visible–near‐infrared transmittance spectra in the 300–3000 nm range exhibit near 80% transparency in the visible region after annealing. Furthermore, the estimated bandgap values increase from 2.95 to 3.08 eV as the carrier concentration increases after the heat treatment. The results suggest the superiority of the oxygen‐annealed sample over the other annealing environments.