Highly efficient electroluminescence from SnO₂ nanocrystals and Er³⁺ co-doped silica thin film via introducing Ca²

Efficient and stable near-infrared silicon-based light source is a challenge for future optoelectronic integration and interconnection. In this paper, alkaline earth metal Ca²⁺ doped SiO₂-SnO₂: Er³⁺ films were prepared by sol-gel method. The oxygen vacancies introduced by the doped Ca²⁺ significantly increase the near-infrared luminescence intensity of Er³⁺ ions. It was found that the doping concentration of Sn precursors not only modulate the crystallinity of SnO₂ nanocrystals but also enhance the luminescence performance of Er³⁺ ions. The stable electroluminescent devices based on SiO₂-SnO₂: Er³⁺/Ca²⁺ films exhibit the power efficiency as high as 1.04×10^-2 with the external quantum efficiency exceeding 10%.