Fabrication and characterization of highly luminescent Er3+:Al2O3 thin films with optimized growth parameters

•Erbium doped amorphous alumina thin films were fabricated.•The effects of change in various deposition parameters studied.•Films grown at 450 °C and at 10°sccm oxygen pressure are useful in optics.

Erbium doped amorphous alumina thin films were fabricated using Co-sputtering technique in various depositions runs with varying parameters for optimizing the deposition parameters to obtain the films with best optical performance. The main subject of investigation includes the effects of change in various deposition parameters such as substrate heating, radio frequency (RF) power and oxygen pressure inside the chamber while deposition. High quality as-deposited films with various Er concentrations and low carbon content have been confirmed by XPS. Substrate heating ∼500 °C was found to be very effective in getting highly dense films with high refractive index of 1.70 at 1530–1570 nm emission band. The Er3+-doped films showed very intense near-infrared luminescence peak at 1550 nm even without any post-deposition annealing treatment.