Oxygen defect dominated photoluminescence emission of ScxAl1-xN grown by molecular beam epitaxy

A fundamental understanding and control of impurity incorporation and charge carrier recombination are critical for emerging ScxAl1-xN electronics, optoelectronics, and photonics. We report on the photoluminescence properties of ScxAl1-xN grown by plasma-assisted molecular beam epitaxy with varying growth temperatures and Sc contents. Bright and broad emission comprising a dominant peak at similar to 3.52eV and a weak peak at similar to 2.90eV was observed in Sc0.05Al0.95N. The origin of the similar to 3.52eV emission line is attributed to charge carrier recombination from the localized excited state of (V-cation-O-N)(2-/-) to its ground state, whereas the second peak at similar to 2.90eV results from charge carrier recombination of isolated V cation 3 - / 2 - to the valence band. We further show that oxygen defect-related emission can be significantly suppressed by increasing growth temperature. This work sheds light on the recombination dynamics of photoexcited carriers in ScxAl1-xN and further offers insight into how to improve the optical and electrical properties of ScxAl1-xN that are relevant for a broad range of applications.

Automated summary

This study investigates the photoluminescence properties of ScxAl1-xN materials grown by molecular beam epitaxy, revealing bright and broad emissions in Sc0.05Al0.95N with dominant peaks at around 3.52eV and 2.90eV. The emissions are associated with charge carrier recombinations from localized excited states to ground states, and increasing growth temperature can suppress oxygen defect-related emissions. These findings shed light on the recombination dynamics in ScxAl1-xN and provide insights for enhancing their optical and electrical properties.