Hydrothermal-grown ZnO as a fast-response scintillator and EUV imaging material

Abstract

Next-generation extreme ultraviolet (EUV) applications will require the development of scintillator devices that are capable of fast imaging. As we have demonstrated recently, zinc oxide (ZnO) is a prominent candidate. In this talk, we will present our newest results on the scintillator properties of hydrothermal-grown ZnO crystal. The imaging capabilities of the ZnO scintillator is demonstrated by imaging the beam focal spot of an EUV laser emitting at 13.9 nm wavelength. The fluorescence image of the ZnO crystal was taken and compared with a high-resolution target as reference. The system’s resolving power was determined to be ~5.5 μm/pixel. These results present a feasible method to perform single-shot beam diagnostics for EUV sources using a ZnO scintillator. Additionally, the temporal response of the crystal has been further improved by modifying the crystal growth scheme. Its bandgap-related fluorescence lifetime was less than 100 ps for 290-nm pulsed excitation. Using the 51-nm excitation pulse of the X-Ray Free Electron Laser prototype at the SPring-8 research facility, a response time of ~70 picoseconds was confirmed. These results suggest that the hydrothermal-method grown ZnO is currently the fastest scintillator in the 50-60 nm wavelength.