Photoluminescence properties of Er3+-doped Al2O3 film synthesized from Er-ion-implanted γ-AlOOH xerogel

The Er3+-doped Al2O3 films were prepared by sintering Er-ion-implanted γ-AlOOH xerogel films on SiO2/Si(100) substrates. In a cycle, the γ-AlOOH xerogel films about 50 nm thick were dip-coated using aluminium isopropoxide-derived γ-AlOOH sols; the Er ions were then implanted into the γ-AlOOH xerogel films using an ion energy of 45 keV with different doses of 5 × 1014 to 1 × 1016 ions cm− 2. Er3+-doped Al2O3 films were formed after 1, 2, and 4 cycles of dip-coating and implantation at different sintering temperatures of 800–1200 °C. The photoluminescence (PL) spectra were observed with a main peak at 1.533 μm and a side peak at 1.549 μm for all the Er3+-doped Al2O3 films. The intensity of PL peak of the Er3+-doped Al2O3 film obtained after 4 cycles with 5 × 1015 ions cm− 2 dose at every cycle and sintered at 900 °C for 5 h, increased by about 10 and 3 times compared with that of the films obtained after 1 and 2 cycles. At the same sintering temperature of 900 °C, the intensity of PL peak of the Er3+-doped Al2O3 films first increased with the increase of dose from 5 × 1014 to 5 × 1015 ions cm− 2 at every cycle, and then a saturation tendency was observed when the dose further was increased to 1 × 1016 ions cm− 2. For the samples using 5 × 1015 ions cm− 2 dose at every cycle, the PL intensity increased with the increase of sintering temperature from 800 to 1200 °C.