Low power consumption light emitting device containing TiO₂:Er³⁺ thin film prepared by sol-gel method

Er³⁺ ions doped titanium dioxide (TiO₂) thin films have been prepared by sol-gel method. The photoluminescence both in visible light range (510-580 nm and 640-690 nm) and near infrared light range (1400-1700nm) have been observed. The photoluminescence excitation spectra demonstrate that energy transfer from wide band-gap TiO₂ to Er³⁺ ions causes the infrared light emission. It is also found that the post annealing temperature can influence the luminescence intensity significantly. Based on sol-gel prepared TiO₂:Er³⁺ thin films, we fabricate light emitting device containing ITO/TiO₂:Er³⁺/SiO₂/n⁺-Si/Al structure. Both the visible and near infrared electroluminescence (EL) can be detected under the operation voltage as low as 5.6 V and the working current of 0.66 mA, which shows the lower power consumption compared with the conventional EL devices.