Yttrium antisite reduction and improved photodiode performance in Ce doped Y3Al5O12 by Czochralski growth in alumina rich melts

Abstract

Single crystal cerium doped yttrium aluminum garnet boules were grown by the Czochralski method. Cerium concentrations were held at 1.0 at. % (with respect to yttrium in an on stoichiometric charge) but melt stoichiometry ranged from 10.0 at. % yttria rich to 10.0 at. % alumina rich in 5.0% increments. Photo-luminescence, lifetime, and scintillation data demonstrate a measureable decrease in UV defect emission as the melt becomes alumina rich. This is strongly consistent with a suppression of equilibrium YAl3+ antisite defect concentrations in the boule as melt stoichiometry shifts towards alumina rich. This decrease does not alter thermoluminescence behavior, making the case that carrier traps and YAl3+ antisites are independent defects. Additionally, an aluminum in-diffusion post growth treatment indicates the observed change is from reduction of YAl3+ antisite defect concentrations alone, as opposed to alteration of antisite-vacancy complexes. The results culminate in a large increase in visible emission and produce an excellent resolution of 5.04 ± 0.07% (662 keV; 10 mm thick) with electronic noise subtraction on a photodiode.

Properties of Ce3+-Doped Y3Al5O12Phosphor Nanoparticles Formed by Laser Ablation in Liquid

“…6. 31,32 Furthermore, the PL peak wavelength for the suspension shifted from 535 nm to 510 nm, as mentioned in Fig. 11.…”

“…Therefore, the suspension suggests to improve the crystal quality and has stronger PL intensity with increasing the laser energy density, compared with the precipitation. 31,32 Meanwhile, the decay time of all the generated nanoparticles was longer than that for the target (3.3 ns). This result suggests that the lattice defects increased during the generating nanoparticle.…”

“…This phenomenon suggests that the lattice defect contained and had larger amount of the defect for the precipitation. 31,32 Meanwhile, it is considered that the lattice defects decreased with increasing the laser energy density for the suspension. These results were similar to the calculated crystallite sizes conducted with the XRD and measurement of PL intensity, as shown in Figs.…”

Recent progress in advanced optical materials based on gadolinium aluminate garnet (Gd3Al5O12)

“…GAG-based single crystals and transparent ceramics with Ce 3+ as the activator are shown to have fast scintillation decay and high light yields, and thus hold great potential as scintillators for a wide range of applications. Anti-site defects commonly exist in aluminate garnets [106–108], and their occurrence and energy level have profound influences on various aspects of emission through interacting with the excited electrons. These issues, however, have rarely been tackled for the GAG-based garnets, either when Lu 3+ or Ga 3+ is used as lattice stabilizer, and thus need to clarify in future studies for a better control of optical properties.…”