Enhanced optical activation of Er 3+ in Er 3+-doped Al 2O 3 powders by Y 3+ codoping in a sol–gel method

Abstract

Enhanced photoluminescence (PL) mechanism of Er 3+-doped Al 2O 3 powders by Y 3+ codoping at wavelength 1.53 μm has been investigated through PL measurements of 0.1 mol% Er 3+- and 0–20 mol% Y 3+-codoped Al 2O 3 powders prepared at a sintering temperature of 900 °C in a non-aqueous sol–gel method. PL intensity and lifetime of Er 3+–Y 3+-codoped Al 2O 3 powders composed of γ-(Al,Er,Y) 2O 3 and θ-(Al,Er,Y) 2O 3 phases increased with increasing Y 3+-codoping concentration. The 10–20 mol% Y 3+ codoping in 0.1 mol% Er 3+-doped Al 2O 3 powders intensified the PL intensity by about 20 times, with a PL lifetime prolonged from 3.5 to 5.8 ms. A maximal increase of the optical activity of Er 3+ in 0.1 mol% Er 3+–Y 3+-codoped Al 2O 3 powders about one order was achieved by 10–20 mol% Y 3+ codoping. It is found that the improved PL properties for Er 3+–Y 3+-codoped Al 2O 3 powders are mainly attributed to enhanced optical activation of Er 3+ in the Al 2O 3 by Y 3+ codoping, and to the slightly increased radiative quantum efficiency of Er 3+ in the Al 2O 3.