4 Citations
This study explores the growth of Liquid Phase Epitaxy (LPE) and investigates the optical and photovoltaic properties of single crystalline film (SCF) phosphors. These phosphors are based on Ce3+-doped Y3MgxSiyAl5−x−yO12 garnets, with varying Mg and Si concentrations ranging from x = 0 to 0.345 and y = 0 to 0.31. The properties analyzed include absorbance, luminescence, scintillation, and photocurrent in comparison with their Y3Al5O12:Ce (YAG:Ce) counterparts. Specially prepared low-concentration (x, y < 0.1) YAG:Ce SCFs, which included Mg2+ and Mg2+–Si4+ codopants, demonstrated increased photocurrents with rising dopant levels. These SCFs consistently exhibited Mg2+ excess in their as-grown state. When exposed to α-particles, these garnets displayed a low light yield (LY) and a rapid scintillation response with nanosecond decay times, attributed to the production of Ce4+ ions compensating for the Mg2+ excess. Post-annealing at temperatures above 1000 °C in a reducing atmosphere (95%N2 + 5%H2) converted Ce4+ back to Ce3+, leading to an LY of about 42% and decay kinetics similar to those of YAG:Ce SCFs. Photoluminescence studies revealed the formation of Ce3+ multicenters and energy transfer among them, influenced by variable crystal field strengths at nonequivalent dodecahedral sites, due to Mg2+ and Si4+ substitution at octahedral and tetrahedral positions, respectively. Compared to YAG:Ce SCFs, the luminescence spectra of Y3MgxSiyAl5−x−yO12:Ce SCFs expanded significantly in the red region. Leveraging these advantageous alterations in optical and photocurrent properties through Mg2+ and Si4+ alloying, a new generation of SCF converters could be developed for applications in white LEDs, photovoltaics, and scintillators.