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This study provided the first in-depth investigation of the effects of large dopant incompatibility (Pr3+ and La3+ ions) on the small host lattice element (Lu3+) in Lu 3 Al 5 O 12 (LuAG) single crystal. The growth of such complex crystals from the melt presented many challenges. By engineering the ionic radius ratio of RE- and M-site cations, a single-crystal phase stabilized by configurational entropy was achieved. This investigation elucidated the crystallization behavior of configurationally disordered rare-earth aluminum garnet oxide (Lu 1−x−y Pr x La y) 3 Al 5 O 12 from the melt and characterized its functional properties, including microstructural, optical, photoluminescence, and scintillation properties, between 5 and 300 K. Relaxation of the imposed strain energy led to local perturbations and destabilization of the garnet structure. Multielemental EDS mapping, micro-Raman spectroscopy, and thermoluminescence revealed the mechanism by which atomic size mismatch drove a smooth transition from the garnet to the perovskite phase in high entropy garnets. The optical, photoluminescence, and scintillation measurements provided fundamental insights into property changes driven by incompatibility doping. Standard and modified Judd-Ofelt theory analysis of absorption spectra determined the phenomenological Judd-Ofelt parameters Ω λ and radiative lifetimes. Atomic size mismatch engineering offers a promising approach to overcoming the limitations of conventional eutectic synthesis methods. • Perovskite inclusions, driven by atomic size mismatch, extend from rim to core. • Controlled incompatible La3+,Pr3+ codoping in LuAG modify functional properties. • Scintillation light yield improved up to 30% in La3+ codoped LuAG:Pr crystals. • (La,Pr)AlO 3 perovskite forms due to size mismatch of La3+ and Pr3+ with Lu3+. • Lattice disorder affects the intensity ratio of Pr³⁺ 5d→4 f and 4 f→4 f emissions. [ABSTRACT FROM AUTHOR]

Several types of dislocations were found in CdWO 4 single crystals. In-grown dislocations slip on (100) plane parallel to [001]. Dislocation pits were revealed in mechanically polished samples on (100) and (010) planes. Based on the results of chemical etching, it was inferred that the lattice dislocations gliding along < 001 > and < 100 > can split into partial dislocations. In the samples annealed at T = 600ºC for 2 h dislocation density decreased noticeably. After annealing shape and sizes of helical etch pits on (100) and (001) planes transform to those typical of lattice dislocations. • Dislocations slip as (100)[001] and (010)[100] in CdWO 4. • Lattice dislocations a[001] or c[001] dissociate. • Partial dislocations ½<101> glide and climb simultaneously. • Dislocation density decreases due to annealing. • Lattice dislocations are restored during annealing. [ABSTRACT FROM AUTHOR]

High-quality lutetium aluminum garnet doped with various Pr3+ concentrations ((Lu 1- x Pr x) 3 Al 5 O 12 , abbreviated to Pr:LuAG) single crystals were grown by the optical floating zone method. The concentration of Pr3+ dependence on microstructure, luminescence and scintillation properties were systematically studied. Based on the results of Rietveld refinement, the doping of Pr3+ leads to lattice distortion and lowers its symmetry. The symmetry of the LuO 8 dodecahedron center is lowest at 0.010, as confirmed by the Raman spectra. When excited at 450 nm and X-rays, the primary emission peak at 614 and 300 nm, respectively, induced by Pr3+ 4 f 2-4 f 2 and 4 f 5 d -4 f 2 transitions. The optimal doping concentration is 0.010. The electric dipole-electric dipole interaction between adjacent Pr3+ was responsible for the concentration quenching in the Pr:LuAG single crystals. (Lu 0.990 Pr 0.010) 3 Al 5 O 12 shows the shortest average scintillation decay time (22.55 ns) and highest light yield (23,842 ± 2300 ph./MeV) under 662 KeV 137Cs gamma-ray irradiation. In terms of overall luminescence and scintillation performance, 0.010 doping was the best for Pr3+ doped LuAG single crystals. • High quality Pr:LuAG single crystal was grown by optical floating zone method. • Pr ions lead to the enhanced translational motion of rare earth ions in Pr:LuAG. • Electric dipole-electric dipole interaction induced concentration quenching of Pr3+. • 0.010 Pr:LuAG single crystal has the best scintillation and luminescence properties. [ABSTRACT FROM AUTHOR]

Bismuth silicate (Bi 4 Si 3 O 12 , BSO) crystal is considered as a promising candidate for fabricating dual-readout calorimeters. Ta 2 O 5 doped BSO crystals were successfully grown by the modified vertical Bridgman method. The crystals possessed about 80% transmittance in the region of 350–800 nm with an absorption edge at about 280 nm. The emission and excitation spectra only showed a wide band which could be ascribed to the typical peaks of Bi3+. The light yield of BSO crystals could be improved effectively by doping Ta 2 O 5 , and the optimized concentration was about 1 mol%, dramatically improving the light output to about 150% of pure BSO crystals. Both the experimental results and theoretical calculations showed that doping Ta5+ ion could reduce the band gap and effectively enhance the light absorption, which was beneficial to generate more electron-hole pairs and promote its emission and light yield. Ta5+ ion is an effective candidate among the transition metal ions for improving the light output of BSO crystals. [Display omitted] • Ta 2 O 5 : BSO crystals with 25 mm diameter and 80 mm length were successfully grown by the modified vertical Bridgman method. • It was showed that Ta5+ improves the light yield of BSO to about 150% of the pure one. • Ta5+ introduces defect levels in the band gap of BSO, which is beneficial to promote the emission and light yield. [ABSTRACT FROM AUTHOR]

Transparent and yellowish Ce-doped SrHfO 3 (Ce:SHO) single crystals were grown by the xenon lamp equipped floating zone method. The synthesized crystals were in the single phase of SHO crystal structure, and no impurity phases such as HfO 2 were evident by the X-ray diffraction analysis. The Ce:SHO shows blue luminescence peaking at 410 nm in both the PL and scintillation spectra, and the decay time constant was approximately 14 ns. The PL QY increases with the Ce concentration, which was confirmed up to 5%. The afterglow level is the lowest when the Ce concentration is 3%. The full energy peak can be demonstrated with all the Ce:SHO single crystals prepared in this study under 241Am alpha-ray irradiation, and the estimated light yield is 396 photons/MeV for the 3% Ce:SHO, which is the highest among the samples studied. • Transparent and yellowish Ce-doped SrHfO 3 (Ce:SHO) single crystals were synthesized by the xenon lamp equipped floating zone method. • Ce:SHO showed blue luminescence with the maximum peak at 410 nm in both the photoluminescence and X-ray-induced scintillation spectra. • The full energy peak was observed in all the Ce:SHO single crystals under 241Am alpha-ray irradiation. [ABSTRACT FROM AUTHOR]

• Mg2+ codoping effect on the atoms segregation in GAGG:Ce single crystal studied. • The formation of defects in Mg2+ and Ce3+ codoped GAGG crystals discussed. • The luminescence quenching mechanism in Mg2+ codoped proposed. • The charge compensation mechanism discussed. • Mg2+ codoping influence on the scintillation and luminescence properties investigated. The undoped, Mg2+ doped, Ce3+ doped as well as Mg2+:Ce3+ codoped Gd 3 Al 2 Ga 3 O 12 crystals were grown from the melt by the micro-pulling down method. Ce3+ and Mg2+ ions were codoped in a wide concentration range. A study of Mg2+ ion concentration effect on the luminescence and scintillation properties as well as segregation of atoms and defects creation processes were carried out. Mg2+ doping in Gd 3 Al 2 Ga 3 O 12 led to the creation of O O • defects localized next to Mg2+ sites due to charge imbalance compensation. Consequently, neutral (Mg Ga/Al/Gd O O) x defects were formed. In Ce3+ doped crystals, Mg2+ codoping changed the valence state from Ce3+ to Ce4+ to maintain charge neutrality. Hence, additional neutral (Ce Gd • -Mg Ga/Al/Gd ′) x and (Ce Gd -Mg Ga/Al/Gd O O) x defects appeared. Moreover, Mg2+ induced charge imbalance in GAGG crystal might also be compensated by the formation of oxygen vacancies (V O •• ). The Mg2+ ions imposed defects deteriorated the segregation of atoms. Accordingly the radial inhomogeneity of the crystals was diminished. The presence of stable Ce4+ and defects imposed by Mg2+ ions codoping were proved by absorption, photoluminescence, and scintillation decay time analysis. Hence, Mg2+ codoping resulted in quenching of the Ce3+ luminescence, acceleration of scintillation response, reduction of light yield, and thermally stimulated luminescence. The mechanism explaining a strong luminescence quenching with increasing Mg2+ ions concentration was proposed. [ABSTRACT FROM AUTHOR]

• The optical constants of Lu 2 O 3 single crystals covering the UV–VIS–NIR spectral region are firstly investigated • The bandgap energy 5.541 ± 0.004 eV of Lu 2 O 3 single crystal is derived experimentally • Large-size and damage-free Lu 2 O 3 single crystal is obtained by chemical mechanical polishing Lu 2 O 3 has attracted widespread attention in high-power lasers, scintillators, and semiconductors due to its high thermal conductivity, high stability, and large band gap. Due to the limitations of the growth process, high-precision characterization of polished quality and optical properties for large-size Lu 2 O 3 single crystal is extremely scarce, which hinders the design and optimization of optics based on Lu 2 O 3. In this study, we design a systematic machining scheme for large-size Lu 2 O 3 single crystal thick chip to obtain polished crystal with virtually no surface and subsurface damage. The surface/subsurface quality was evaluated utilizing optical profilometer, scanning electron microscope, and transmission electron microscope. Variable-angle spectroscopic ellipsometer was employed to measure the optical constants over wide spectral region (210–1690 nm), removing the lack of optical constants of Lu 2 O 3 single crystal in the ultraviolet region. The band gap is analyzed based on the optical constants results. The consistency of the measured data with the relevant literature verifies the reliability and accuracy of the measurement method along with the data. The surface/subsurface damage inspection method provides an effective approach for ultra-precision machining mechanism research and process optimization of Lu 2 O 3 and other hard and brittle materials. The band gap and the optical constants in wide spectral region provide critical fundamental data for the design and performance optimization of related optics. [ABSTRACT FROM AUTHOR]