Multiple channels to enhance near-infrared emission from SiO2–SnO2:Er3+ films by Ba2+ ion doping

Abstract

Ba²⁺ ions co-doped SiO₂–SnO₂:Er³⁺ thin films are prepared using a sol–gel method combined with a spin-coating technique and post-annealing treatment. The influence of Ba²⁺ ion doping on the photoluminescence properties of thin films is carefully investigated. The enhancement of near-infrared (NIR) emission of Er³⁺ ions by as much as 12 times is obtained via co-doping with Ba²⁺ ions. To illustrate the relevant mechanisms, X-ray diffraction, X-ray photoelectron spectroscopy and comprehensive spectroscopic measurements are carried out. The enhanced NIR emission induced by Ba²⁺ co-doping can be explained by more oxygen vacancies, improved crystallinity and strong cross-relaxation processes between Er³⁺ ions. The incorporation of Ba²⁺ ions into SiO₂–SnO₂:Er³⁺ thin films results in a considerable enhancement in the NIR emission, making the thin films more suitable for Si-based optical lasers and amplifiers.