Luminescence of RE-ions in HfO2 thin films and some possible applications

Photoluminescence (PL) of rare-earth (Sm, Eu, Tb) ions in HfO2 thin films has been investigated at 10 and 300 K. Samples were prepared by using the sol–gel and the atomic layer deposition (ALD) methods. An intense PL emission characteristic of 4f-shell transitions of RE3+ ions was observed under the excitation photon energies exceeding the band-gap energy of the host material. The measured PL excitation spectra that were similar to those of intrinsic emission confirmed the efficient energy transfer from the host material to dopants. The kinetics of RE3+ emission revealed a non-exponential behaviour in all studied materials, strongly depending on the thermal treatment of the materials. The results obtained suggest the application potential of RE-doped HfO2 in scintillators as well as in chemical sensors.