Bright exciton luminescence from La doped Lu3Al5O12 single crystals

Abstract

This research dealt with the investigation of luminescence properties of undoped and La doped Lu3Al5O12 single crystals using synchrotron radiation excitation. The influence of La3+ doping on the exciton emission and decay kinetics properties of Lu3Al5O12 single crystals was studied at 7 K and room temperature. Undoped and La3+ doped samples showed bright luminescence in the UV spectral range. In undoped Lu3Al5O12 crystal, the UV luminescence was associated with LuAl antisite defects, which acted as luminescence centers in the band peaked at 295 nm La3+ doping in Lu3Al5O12 crystals caused the formation of LaLu luminescence centers and increased the concentration of LuAl antisite defects. Therefore, the luminescence of La doped Lu3Al5O12 crystals was a superposition of the emission coming from both LaLu and LuAl centers. Furthermore, La3+ doping significantly enhanced the intensity and shifted the UV luminescence of Lu3Al5O12 crystals towards higher energy due to the dominant contribution of LaLu luminescent centers in the band peaked at 275 nm. The decay time of heavily La3+ doped LuAG crystals was also significantly accelerated due to the prevailing luminescence of LaLu centers.