Thin films of HfO2 and ZrO2 as potential scintillators

Emission, excitation and absorption spectra of HfO2 and ZrO2 thin films grown by atomic layer deposition were investigated in the temperature range of 10-300 K. Time-resolved luminescence spectra were excited with a pulsed ArF laser and tuneable synchrotron radiation in UV-VUV. The strong emission with the peak position at 4.2-4.4 eV and with the decay time in μs range was revealed at 10 K in both materials. The emission was ascribed to the radiative decay of self-trapped excitons (STE). the features observed in the absorption and excitation spectra at 5.8 and 5.4 eV were most probably due to the formation of excitons; While the interband transitions started to dominate at 6.15 and 5.85 ev in HfO2 and ZrO2, respectively.