Effect of growth conditions on Eu3+ luminescence in GaN (original) (raw)

Eu-doped GaN thin films were in situ grown on sapphire substrates by RF plasma-assisted solid-source molecular beam epitaxy technique. Strong red emission at $ 622 nm from 5 D 0 -7 F 2 radiative transitions in Eu 3 + ions was observed for all samples. The effects of important growth parameters, such as III/V ratio (Ga flux), Eu cell temperature (Eu flux) and growth temperature, on Eu 3 + photoluminescence were studied. X-ray diffraction and secondary ion mass spectroscopy measurements were performed to investigate thin film quality and Eu doping profiles. The strongest Eu 3 + luminescence was obtained from GaN:Eu thin films grown under slightly N-rich condition (III/V o 1), while the highest Eu 3 + emission efficiency was obtained in thin films grown under Ga-rich condition (III/V Z 1). The optimum Eu doping concentration for Eu 3 + luminescence is $ (0.1-1.0) at% for III/V r 1 ratio condition. Higher growth temperature ( 4 750 1C) was also found to enhance Eu 3 + luminescence intensity and efficiency.