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RESEARCH PRODUCT

ZnO and ZnO:Ga Ceramics for Advanced Scintillators

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The undoped ZnO reveals narrow luminescence bands located close to fundamental absorption edge, known as near band luminescence (NBL) and defects related wide luminescence band within visible range of spectrum. NBL decay is in sub-nanosecond range and it is promising for fast scintillator development. However, the defects luminescence decay is in microsecond range and it is disturbing for fast scintillators. Dopants strongly change the luminescence properties, mainly the intensity and decay time and that is the cause for intense study of doped ZnO luminescence properties. Thus the study of luminescent properties of undoped ZnO and doped ZnO:Ga ceramics was carried out. The dependence of the radioluminescence intensity on temperature and spectrum of near band edge luminescence were examined. NBL spectra comparison of ZnO and ZnO:Ga ceramics with ZnO:Ga single crystal allowed drawn out that at 300 K the donor-acceptor pair luminescence is dominant. It was suggested that the reabsorption within band edge spectral region could significantly affected the near band luminescence intensity and spectral position at 300 K. The significant impact of gallium on the ZnO luminescence is observed. The decay kinetics of luminescence were studied in picosecond range and the two-stage luminescence decay was found for undoped ZnO. The fastest decay stage time is determined to be within 37 – 57 ps. One stage decay kinetics of NBL was determined for ZnO:Ga ceramic and decay time of 17 ps was estimated.