Features of the Interpretation of the Luminescence Spectra of Zinc Oxide Films on Sapphire

• Published in: Inorganic materials : applied research 2021-03, Vol.12 (2), p.343-346
• Main Authors: Ismailov, A. M., Muslimov, A. E.
• Format: Article
• Language: English
• Subjects: Annealing; Beam leads; Cathodoluminescence; Chemistry; Chemistry and Materials Science; Film thickness; Industrial Chemistry/Chemical Engineering; Inorganic Chemistry; Luminescence; Materials of Electronic Engineering; Materials Science; Optical properties; Oxide coatings; Recrystallization; Sapphire; Spectra; Substrates; Thin films; Zinc oxide; Zinc oxides
• ISSN: 2075-1133; 2075-115X
• DOI: 10.1134/S2075113321020180

The features of the interpretation of the spectral dependence of the luminescent properties of ZnO films on sapphire are presented. ZnO films of various thicknesses obtained in an oxygen atmosphere at various substrate temperatures, including the stage of recrystallization annealing, are considered for a comprehensive analysis. It is shown that, in the cathodoluminescence spectrum of thin ZnO films obtained at a low substrate temperature, only the red (650–1000 nm) band of the sapphire substrate is observed, and the luminescence of the ZnO film is suppressed by excessive defectiveness. Prolonged recrystallization annealing results in improved quality of thin ZnO films and the appearance of a wide (430–740 nm) band in ZnO. With an increase in the substrate temperature and film thickness, only the bands associated with ZnO are revealed in the cathodoluminescence spectra: an edge luminescence band (with maximum at 390 nm) and a red band (at 500–950 nm with a maximum near the region of 710 nm) associated with charged vacancies of zinc. Focusing the beam leads to local heating of the sample and an increase in the concentration of interstitial zinc. Related to this is the shift of the edge luminescence band to the 410 nm region, as well as blue mixing of the band of defect luminescence.