Visible and infrared emissions from $c$-axis oriented AlN:Er films grown by magnetron sputtering

Visible and infrared photoluminescence was observed from AlN:Er films grown by reactive radio-frequency magnetron sputtering under different powers. X-ray diffraction indicates that the films have a $c$-axis oriented hexagonal wurtzite structure with an average crystallite size of about $59–83nm$ and a strain of about $(1.12–1.69)×10−3$⁠. Green emissions (⁠$∼540$ and $558nm$⁠) from the AlN:Er films are due to the intra-$4fn$ transition of $Er3+$ from $H11∕22$ and $S3∕24$ to $I15∕24$⁠, and infrared $(∼1535nm)$ emissions correspond to $I13∕24$ to $I15∕24$ transitions. Increasing the sputtering power results in larger grain size, lower strain, and enhancement of the luminescence intensity.