Enhanced cathodoluminescence from an amorphous AlN:holmium phosphor by co-doped Gd+3 for optical devices applications

摘要

Sputter-deposited thin films of amorphous AlN:Ho (1 at. %) emits in the green (549 nm) region of the visible spectrum under electron excitation. The addition of Gd (1 at. %) in the film enhances the green emission linearly after thermal activation at 900 degrees C for 40 min in a nitrogen atmosphere. The luminescence enhancement saturates when the gadolinium concentration reaches four times the holmium concentration. The optical band-gap of amorphous AlN is about 2 10 nm, so that the film is transparent in the ultraviolet, allowing us to observe the ultraviolet emission at 313 run from Gd. No significant quenching of the Gd emission is observed. Energy dispersive x-ray (EDX) spectra confirm the increasing concentration of Gd. X-ray diffraction (XRD) analysis shows no peaks other than those arising from the Si (111) substrate, confirming that the films are amorphous. The enhanced luminescence can be used to make high-efficiency optical devices.