Shallow traps and radiative recombination processes inLu3Al5O12:Cesingle crystal scintillator

Abstract

Thermally stimulated luminescence ͑TSL͒ glow curves and emission spectra were studied in undoped and Ce-doped Lu 3 Al 5 O 12 single crystals by wavelength resolved TSL measurements in the 10-310 K temperature range. Isothermal phosphorescence measurements in the 10-100 K range were also performed, which point to the existence of a tunneling-driven radiative recombination process. These processes can explain the presence and time-dependence of the submicrosecond slow decay component in the scintillation decay. Electron paramagnetic resonance experiments suggest the presence of Lu Al defects in the vicinity of Ce 3+ ions, which are the most probable electron and hole traps participating in the tunneling-driven radiative recombination process.

Electronic excitations and defect creation in wide-gap MgO and Lu3Al5O12 crystals irradiated with swift heavy ions

“…6). The figure also presents the excitation spectrum for a broadband emission peaked at ~4.5 eV, which is conclusively interpreted in the literature as the emission of antisite defects Lu| Al -Lu 3+ ion at Al 3+ site [18,43]. The concentration of such as-grown antisite defects is significantly lower in a thin crystalline film of LuAG, prepared by liquid phase epitaxy technology at about 1000 ºC, i.e.…”

“…In YAG, the low-temperature emission at 4.9 eV is convincingly attributed to the radiative decay of mobile anion excitons [20,43,47]. However, these excitons differ strongly from the free excitons with line absorption and emission spectra in MgO as well as from "self-shrunk" excitons in α-Al 2 O 3 , which give a broadband emission (~7.6 eV) at the excitation by 9.1 eV photons [48].…”

Comparative Study of Nonproportionality and Electronic Band Structures Features in Scintillator Materials

“…Experimental evidence that explicitly quantifies the relative proportion of free charge carriers to excitons has not been found in the literature. However, the scintillation mechanisms in YAP and LuAP [37,38], YAG and LuAG [39,40], YSO [41], LSO [ 42,43], and BGO [44][45][46] have been shown to involve shallow and deep electron and hole traps, therefore suggesting the predominance of free carriers over excitons. The dependency observed in Fig 2b for these scintillator materials, indeed suggests that free electrons and holes are the main energy carriers.…”

Thermal ionization and thermally activated crossover quenching processes for5d−4fluminescence inY3AlUeda1, Meijerink2, Dorenbos3 et al. 2017Phys. Rev. B642420View full textAdd to dashboardCite

“…Note that not all the ionized electrons recombine with the photo-oxidized luminescent center nonradiatively. Some of the ionized electrons can transfer back to the 5d excited state immediately or after trapping to intrinsic defects and detrapping processes (persistent luminescence and delayed recombination luminescence) [8,9]. In any cases, thermally activated photoionization leads to a reduced light output.…”