Ultraviolet spectroscopy of Pr+3 and its use in making ultraviolet filters

Sputtered deposited thin films of AlN:Pr and GaN:Pr emit in ultraviolet–visible and visible regions of the spectrum, respectively, under electron excitation in cathodoluminescence apparatus. The goal is to study the ultraviolet emission from Pr+3 when doped in nitride semiconductor hosts. Luminescence peaks at a wavelength of 295 nm (4.2 eV), 335 nm (3.7 eV) and 385 nm (3.24 eV) are observed as a result from 1S0 → 1G4, 1S0 → 1D2 and 1S0 → 1I6 transitions, respectively. However the 1S0 → 1G4 and 1S0 → 1D2 transitions are not observed when Pr+3 is doped in GaN host. The bandgap of GaN absorbs the ultraviolet radiation emitted from Pr+3 and hence GaN can be used as ultraviolet filter for radiation shielding and protection purposes. AlN is transparent to ultraviolet due to its wide bandgap of 6.2 eV.