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

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.