ZnO Grains Research Articles

Atomic layer deposition of diethylzinc/zinc oxide on InAs surface quantum dots: Self-clean-up and passivation processes

Passivation capping of molecular beam epitaxy (MBE)-grown InAs surface quantum dots (SQDs) is achieved by ex situ atomic layer deposition (ALD)-grown ZnO using diethylzinc (DEZ) as the zinc precursor, the main passivation agent, and oxygen plasma. Photoluminescence (PL) intensity is enhanced by 2-fold as the DEZ/ZnO passivation cap thickness reached 30 nm. Atomic force microscopy (AFM) and scanning electron microscopy (SEM) show that contrary to conventional wet chemistry passivation or MBE capping, in which InAs SQDs can be damaged or be shrunken by intermixing of In and Ga, DEZ/ZnO passivation capping almost preserves the shape of the underlying SQDs. The cross-sectional analysis with transmission electron microscopy (TEM) reveals the formation of the ZnO grains on top of the sample accompanied by slight SQD height and width reduction, which are presumably related to the removal of the InAs native oxides. The DEZ “self-clean-up” passivation mechanism, where zinc precursor is responsible for reduction of the surface non-radiative recombination sites, is studied by X-ray photoelectron spectroscopy (XPS). The factors that control the DEZ “self-clean-up” efficiency such as the chain of chemical reactions, steric hindrance, decomposition activation energy, Gibbs reactivity, or Lewis acidity, are evaluated. The results are discussed in comparison with trimethylaluminum (TMA), a precursor used for Al2O3 deposition. We find that the “self-cleaning” by DEZ and TMA occurs through processes of different chemical nature.

SnO2 Doping Effect on the Microstructural and Electrical Behavior of ZnO nanoparticles-Bi2O3 Based Varistor Ceramics

In the current study, ZnO-Bi2O3 varistors manufactured from ZnO nanoparticle size and doped with SnO2 were processed by the ceramic industrial technique. The impact of the various SnO2 concentration upon the sintering, microstructural improvement and nonlinearity characteristic of the varistor system was investigated. Different SnO2 concentration was found to possess considerable influences on the varistors, particularly on improving ZnO grains growth at a lower SnO2 amount. But, the adding of greater contents of SnO2 leads to inhibit the ZnO grain growth via the raising percentage of Zn2SnO4 type spinel phase. In discs with a Sn/Bi less than 1.5 mol%, the pyrochlore phase forms and bounds all the SnO2, whereas excess Bi2O3 leads to the formation of a liquid phase at 740 °C which promotes sintering process. For Sn/Bi more than 1.5 mol%, all the Bi2O3 is bounded in Bi2Sn2O7 pyrochlore phase and sintering process is prevented. X-ray diffraction investigated that additive of SnO2 to the ZnO-Bi2O3 varistor sample caused the structure of the Bi2Sn2O7 type pyrochlore phase and the Zn2SnO4 type spinel phase during the sintering step. The SnO2 adding furthermore noticeably affected the electrical behaviors of the sample with a significant rise in the breakdown voltage with increasing the SnO2 doping more than 1.5 mol%. The resistivity also achieved an obvious increase with increase the SnO2 doping contents. Moderate SnO2 doping enhanced the nonlinear properties of the ZnO-Bi2O3 varistor system, while a significant amount of SnO2 causing its deterioration.

Grain size and sintering temperatures effects on the mechanical properties of ZnO nanoparticle-based varistor ceramics

The grain size impact on the behavior of ZnO–Bi2O3–Mn2O3 varistors was determined in this study. Samples with different sintering temperatures and times were prepared via traditional ceramic methodology, and their properties were described. Results exhibited that various temperatures and times of the sintering process had considerable effects on the varistors. In particular, the growth of ZnO grains was improved at a minimal-temperature sintering process of 900 °C for 1 h. Significant solid-state reaction even at lower sintering temperatures perhaps caused the surface characteristics of ZnO nanoparticles. Vickers indentation analyses were applied to define the fracture toughness and hardness of the samples. Hardness diminished with the growth of ZnO grain. Fracture toughness did not exhibit any change with the increase in grain size (~ 5.1 MPam0.5) up to 1.6 μm for WZ-V and 3.5 μm 20Z-V. Above these grain sizes, a spontaneous conversion from hexagonal to monoclinic phase occurred. WZ-V and 20Z-V samples were used to investigate the analogous bending strength at 1152 and 1148 MPa, respectively. The structural coarsening desired for realizing significant grain size led to increased scattering strength values, as evidenced by lesser Weibull modulus (9.23 vs. 5.10). Variations in the mechanical behavior of the investigated varistors with different grain sizes were demonstrated, and their probable reasons were discussed in brief.

Defect-mediated energy transfer in ZnO thin films doped with rare-earth ions

The rare-earth (RE) (Eu, Er, Nd) doped ZnO thin films were fabricated by a cost-effective chemical solution deposition method. The emission properties of ZnO:RE films were investigated under different excitation conditions, where the RE ions were excited either through direct pumping into the 4f energy levels of RE ions or through indirect excitation by energy transfer from the host material. It is demonstrated that under both excitation methods, the films showed strong emission from the RE ions at room temperature, which confirms the hypothesis that the RE ions can be effectively excited by the host material. Moreover, the influence of RE doping on the development of the crystalline structure of the ZnO thin film was studied. Only a small amount of REs was incorporated into the ZnO grains; most of the REs remained segregated at the grain boundaries, forming a thin oxide shell that strongly suppresses the sintering of the grains and reduces their size.

Influence of Co2O3 doping on the microstructure and electrical properties of ZnO–Bi2O3-based varistors

In this work, the microstructure (for instance grain size and elemental distribution) and comprehensive electrical performances of ZnO–Bi2O3–Cr2O3–MnO2 varistors, with various amounts of Co2O3 prepared via the traditional solid-state sintering method were investigated. The influences of Co2O3 doping on the microstructure of the ZnO varistors were evaluated via X-ray diffraction (XRD), scanning electron microscopy (SEM), and energy-dispersive spectrometer (EDS), while the effects on the electrical performance of the ZnO varistors were analyzed via voltage source meter and inductance-capacitance-resistance meter. The experimental results indicate that Co2O3 doping can contribute to improve the electrical characteristics of ZnO varistors. The double Schottky barrier height φb and nonlinearity coefficient α was enhanced significantly. Meanwhile, Co2O3 doping can effectively reduce ZnO grain resistivity ρg and increase grain boundary resistivity ρgb. In this research, there was an optimal content of Co2O3 (0.5 mol%), the α of the ZnO varistors reaches the maximum value of 46.7 and the φb reaches the maximum value of 0.63 eV with the optimal content.

Equimolar ZnO-CdS nanocomposite for enhanced photocatalytic performance

Nanocomposite of ZnO-CdS having an equal molar ratio (1:1) of the two components has been synthesized using chemical co-precipitation method, with optimized parameters for efficient photocatalytic properties. A variety of suitable techniques including synchrotron based extended X-ray absorption fine structure (EXAFS) have been used to investigate structural, morphological and optical properties of the nanocomposite. The synthesized nanostructured ZnO-CdS nanocomposite is found to have homogenously distributed crystalline grains of both ZnO and CdS. The uniform distribution of grains and the equal molar ratio of the two components have resulted in excellent optical and photocatalytic performance. The UV-Vis absorption spectrum of nanocomposite shows absorption behavior, extended almost uniformly in the entire UV-visible region, with a red shift in the optical band gap of ZnO, suggestive of efficient photocatalytic ability. The photoluminescence spectrum shows the absorbance in both UV and visible regions, corresponding to the near-band-edge emissions of the ZnO and CdS, respectively. Finally, the photocatalytic performance has been studied in photodegradation of methylene blue dye, showing an enhanced efficiency of almost 99% in 110 min, much higher than that of pristine ZnO, as well as CdS and one of the best reported in the literature.

Effect of Ho2O3 doping on the microstructure and electrical properties of ZnO–Bi2O3–Sb2O3–Cr2O3–Co2O3–MnO2-based varistors

Ho2O3 doped ZnO–Bi2O3–Sb2O3–Cr2O3–Co2O3–MnO2-based varistors (ZBSCCM based varistors) was fabricated by solid-state reaction and subsequent sintering process. Microstructure characterization by X-ray diffraction (XRD) and scanning electron microscopy (SEM) indicated the Ho2O3 phase with the doping content no more than 0.8 mol% was distributed along the grain boundaries of ZnO grains and could restrain the growth of ZnO grain. However, excessive Ho2O3 doping (>1.0%) delayed the full densification of the green pellets, leading to the decrease in relative density of the sample. The electrical properties were investigated by means of direct current measurement. It was found that proper amount of Ho2O3 doped in the ZBSCCM based varistors was able to improve the electrical properties. Particularly, the varistor doped with 0.8 mol% of Ho2O3 possessed the highest breakdown field (1578.5 V/mm), an excellent nonlinear coefficient α (86.3) and a small leakage current density (1.06 μA/cm2).

Sensitivity of electrical behaviours of ZnO nanoparticle–Bi2O3–Mn2O3 varistor system to various La2O3 doping compositions

The effects of La2O3 on the behaviours of ZnO nanoparticle–Bi2O3–Mn2O3 varistors were determined. The discs with various La2O3 compositions (0.0–3.0 mol%) were prepared via traditional ceramic techniques and their characteristics were investigated. The results demonstrate that La2O3 remarkably affects the varistor samples, in which the size of grain diminished from 29.3 to 8.5 µm according to increasing La2O3 content from 0.0 to 3.0 mol%. The significant response within the varistor sample fabricated from ZnO nanoparticles through sintering process at 1200oC perhaps caused by the surface properties of the powdered ZnO nanoparticles. X-ray diffraction results show that the addition of La2O3 to the varistor resulted in additional peaks, which can be attributed to the construction of La-based phases through the sintering process at high temperature. The spinal phases of the (Bi48ZnO73) and (Mn3O4) diminish with the 3.0 mol% content of La2O3. The varistor samples with 2.0 mol% La2O3 show a superior spinal phase construction of (Bi48ZnO73) and (Mn3O4) and La-based phases, resulting in homogeneous grain size. La2O3 doping substantially enhanced the electrical behaviours of the disc sample with a notable increase in breakdown voltage from 2614.8 to 5730.7 V/mm caused by the increase in La2O3 doping concentration from 0.0% to 3.0 mol%. The improvement was associated with the potential lanthanide ion segregation caused by its greater ionic radius to the boundaries between ZnO grains, thus enhancing its electrical properties. Moderate La2O3 doping concentration at 1.0 mol% improved the non-linear characteristics of the sample (α = 66) and 4400 V/mm breakdown voltage was introduced, while a significant amount of La2O3 doping concentration (more than 1.0 mol%) caused its deterioration (α = 35). The increase in donor concentration Nd to 2.1 × 1020 cm−3 for the varistor doped with 1.0 mol% La2O3 is accompanied by a decrease of interfacial states density NIS to 2.2 × 1012 cm−2 eV−1, in addition to decrease in depletion layer ω to 3.9 nm. The leakage currents of the sample decreased from 0.473 to 0.310 mA/cm2 with the increase of La2O3 doping contents from 0.0% to 2.0 mol% and then increased to 0.596 mA/cm2 at 3.0 mol% La2O3 doping concentration. Therefore, La2O3 may be added to dominate the microstructural characteristics and electrical behaviours of ZnO–Bi2O3–Mn2O3 varistor manufactured using powdered ZnO nanoparticles.

Tuning the dielectric characteristics and energy storage properties of Ni-ZnO/rGO nanocomposite

In the present study, pure and Ni-doped ZnO/rGO nanocomposites (NCs) are reported using the cost-effective wet chemical route to explore their dielectric characteristics. The structural examinations using X-ray diffraction (XRD) exposed the hexagonal wurtzite structure in both pure and Ni doped ZnO samples. The presence of an additional secondary phase accredited to NiO was also observed in Ni doped sample. The microstructural investigations using scanning electron microscope (SEM) revealed that Ni addition in ZnO modified particle size, shape, and distribution. Using tunneling electron microscope (TEM), it demonstrated that nanoparticles are well distributed in rGO sheets. The dielectric constant and dielectric loss of NCs increased with rGO addition at low frequency region. The relatively higher observed value of the dielectric constant while lower loss is explained on the basis of oxygen vacancies generated. The ac conductivity of NCs increased gradually with frequency due to the tunneling and hopping mechanisms. These results demonstrated that the higher carrier generations at the interface between rGO and ZnO grains are due to the increased mobility of charge carriers. Thus, the synergetic effect among them has the potential for use in advanced microelectronic devices, for instance, a gate material in transistors, capacitance-based energy storage devices etc.

Microstructural evolution of ZnO via hybrid cold sintering/spark plasma sintering

In this work, we demonstrate a hybrid cold sintering/spark plasma sintering (CSP-SPS) process to densify ZnO ceramic with controlled grain growth. The densification of ZnO is initially activated at 85 °C, and high densities (>98%) are achieved at 200–300 °C in only 5 min with a low assisted pressure of 3.8–50 MPa. The microstructure of ZnO grains experiences a mild coarsening from ~205–680 nm during the CSP-SPS. In comparison, a much higher temperature (>770 °C) is required to sinter ZnO ceramic via SPS, and the grain size exhibits an obvious overgrowth to ~10 µm. The calculated apparent activation energy of grain growth using CSP-SPS is 69.3 ± 6 kJ/mol, which is much lower than that of SPS samples with 296.8 ± 59 kJ/mol. In addition, the conduction mechanism of the CSP-SPS and SPS samples is investigated using impedance spectroscopy. Overall, CSP-SPS is promising for the fabrication of fine ceramics with mild sintering conditions.

Electrical and microstructural evaluation of ZnO varistor ceramics with different CaSiO3 contents

In the present study, the impact of CaSiO3 addition on microstructure and electrical characteristics of a ZnO-based varistor system was investigated. The ceramic materials were prepared by solid-state reaction route by varying the CaSiO3 concentrations (0, 3, 6, 9, 12, and 15 wt%) and sintered at 1300 °C. Characterization of the pelletized samples was carried out by density measurement, scanning electron microscopy, energy dispersive X-ray, X-ray diffraction, and current density-electric field characteristics measurement. The growth of ZnO grain was restrained with the introduction of CaSiO3; the average grain size decreases from 18.09 to 10.85 μm, whereas their relative density increases up to 99.79%. Structural results indicated the existence of the CaSiO3-rich phase without any other secondary phase formation. It is also revealed that different CaSiO3 contents significantly affect the electrical properties, prominently in the sample with 12 wt% CaSiO3 addition. The maximal value of the nonlinear coefficient, breakdown voltage, and barrier height acquired in this work were 4.41, 0.80 V/mm, and 0.691 eV, respectively, along with a sharp decline in leakage current density to 373.93 μA/cm2. Further increase in CaSiO3 content (15 wt%) eventually caused a deterioration in varistor behavior.

Improved performance of near UV-blue n-ZnO/p-GaN heterostructure LED with an AlN electron blocking layer

High quality single crystalline n-type ZnO films, with a thickness of 200 nm, were grown on top of AlN/GaN layers under 25 W, 50 W and 100 W sputtering powers. The AlN and p-type GaN layers were deposited by metalorganic chemical vapor deposition (MOCVD). From X-ray diffraction measurements, the samples exhibited the (000l) peaks corresponding to both ZnO, GaN and AlN monocrystalline layers. As the sputtering power was increased, the ZnO grain size increased and the dislocation density decreased. This result is supported by a reduction of the rms values obtained on the ZnO layers from Atomic Force Microscopy (AFM) results. In addition, photoluminescence peaks of ZnO at 372 nm, 375 nm and 380 nm were seen as dependent on the sputtering power. We have used an AlN electron blocking layer between ZnO and GaN films to improve the electroluminescence from the n-ZnO side. Room temperature electroluminescence (EL) of the LEDs demonstrated near UV-blue emission consisting of predominating peaks centred at 405 nm, 390 nm and 380 nm for the device with ZnO deposited at 25 W, 50 W and 100 W sputtering powers, respectively. Moreover, the I-V curves of the LEDs showed a rectifying behavior with 6.8 V, 6.4 V, 5.2 V threshold voltages for 25 W, 50 W and 100 W values.

Optimization of UVB photodiode based on ZnO nanorod arrays grown via the hydrothermal process

In this work, n-Type ZnO nanorods (NRs) were grown on a p-type Si (100) substrate using the hydrothermal technique. These p-n heterojunctions were made to fabricate ZnO-based ultraviolet (UV) photodiodes (PDs). To study the effect of solution volume -in the hydrothermal process-on the structural properties of the ZnO NRs arrays, three samples were prepared with different conditions. SEM characterization shows the well-aligned ZnO NRs arrays grown on all three substrates. X-ray diffraction characterization indicates the crystalline structure of all samples with a preferred orientation of c-plane (002). XRD results show the ZnO grain size enlargement concerning solution volume. To analyze the electric characterization of the samples, the current-voltage (I–V) analysis was performed under dark and illuminated conditions. The I–V measurement indicates that the increase of growth solution volume is leading to increasing in the responsivity of ZnO-based PDs. Additionally, the PL and UV–Vis characterizations exhibit that the optical properties of samples were also affected and therefore could be controlled and optimized by growth conditions.

The Grain Growth Control of ZnO-V2O5 Based Varistors by PrMnO3 Addition.

In this study, the grain growth behaviour of ZnO-V2O5-based ceramics with 0.25–0.75 mol% additions of PrMnO3 was systematically investigated during sintering from 850 °C to 925 °C. with the aim to control the ZnO grain size for their application as varistors. It was found that with the increased addition of PrMnO3, in addition to the decrease in the average grain size, the grain size distribution also narrowed and eventually changed from a bimodal to unimodal distribution after a 0.75 mol% PrMnO3 addition. The grain growth control was achieved by a pinning effect of the secondary ZnCr2O4 and PrVO4 phases at the ZnO grain boundaries. The apparent activation energy of the ZnO grain growth in these ceramics was found to increase with increased additions of PrVO4, hence the observed reduction in the ZnO grain sizes.

Structural, Morphological and Optical Properties of (Mn, Al) Co-Doped ZnO Thin Films Prepared by Sol-Gel Dip Coating Method

In this study, Aluminum (Al) and Manganese (Mn) co-doped ZnO thin films were successfully synthesized into glass substrates by the sol-gel dip-coating method with different Al concentrations (1%, 3%, and 5%). The structural, morphological, and optical properties of the obtained thin films were characterized by X-ray diffraction (XRD), Atomic force microscopy (AFM), and UV–VIS spectroscopy. XRD pattern revealed that the films have a polycrystalline hexagonal structure with a preferred orientation along (101) for undoped ZnO thin films, further the co-doped ZnO thin films show a shift in the preferred orientation to (002) direction without any Mn or Al related phases. The morphological analysis showed that the films have a uniform and dense ZnO grains, without any voids and cracks, and it was found that the surface roughness (RMS) increases from 8,27 to 14,43 nm when the Al doping concentration increased from 1% to 3%; however, when Al doping concentration is 5%, the RMS value decreased to 2,80 nm. From the optical analysis, the higher average transmittance was found to be corresponding to 5% Al doping concentration.

Altering interfacial properties through the integration of C60 into ZnO ceramic via cold sintering process

A lot of nanocomposites containing C60 have been developed to enable various application opportunities. However, it seems impossible to incorporate C60 into ceramics without destroying the C60 molecules, because ceramics are typically sintered at high temperatures that could result in the chemical reaction of C60. Herein, we report the successful integration of C60 with ZnO using cold sintering process. (1-x)ZnO-xC60 composites with x ranging from 0 to 5 wt% are densified into monolithic structures with relative densities over 95%. Clear C60 molecules are observed in the cold sintered composites, and thin C60 layers with less than 10 nm are located at the ZnO grain boundaries. With C60 altering the interfacial structures of ZnO ceramics, the electrical properties are improved significantly, especially, the breakdown electric field at 1 mA cm−2 is enhanced from ∼80 V mm−1 to ∼2100 V mm−1. The FEM analysis indicates that the current density at the interfaces of ZnO and C60 is higher than other regions. This work thus indicates that cold sintering process provides a promising pathway to design new types of functional materials through the integration of C60 and ceramics.

Fabrication of high voltage gradient ZnO nanoparticle-Bi2O3-Mn2O3-based thick film varistors at various sintering temperature

In this research, 20 nm zinc oxide nanoparticles were utilized to fabricate significant voltage gradient zinc oxide nanoparticle-Bi2O3-Mn2O3-based thick film varistors (TFVs) by applying screen printing method. Different low temperatures during the sintering process had a considerable effect on the zinc oxide nanoparticle-based TFVs. In particular, the low temperatures improved the growth of ZnO grains, which was obvious even at 550 °C. The huge surface area of the 20 nm zinc oxide encouraged an intense surface interaction even at minimal sintering temperatures. The sintering technique also enhanced the internal structure of the crystal. Minimizing the fundamental compressive stress depended on the XRD lattice constant and the FWHM analysis. The variable temperatures of the sintering process considerably impacted the electrical behaviours of the samples. A remarkable increase in the voltage gradient of the varistor sintered up to 5732.5 V/mm at 700 °C was observed. The electrical resistivity dropped dramatically from 621.8 kΩ.cm (varistor at 550 °C) to 147.3 kΩ.cm at 800 °C sintering temperature. The small size of grains with perfect boundaries was the main reason for the enhancement of the voltage gradient. The optimal electrical characteristics with a 63 nonlinearity coefficient and 103 μA leakage current were achieved in the varistor sintered at 700 °C. Moreover, maximum permittivity and minimum dissipation factor were attained through the minimal frequency range. Therefore, the sintering process could be applied as a novel technical approach for the dominant voltage gradient of zinc oxide nanoparticle-based TFVs with enhanced microstructural and electrical behavior and good nonlinearity.

Effects of Ta2O5 on the microstructure and electrical properties of ZnO linear resistance ceramics

ZnO linear resistance ceramics were synthesized from ZnO–Al2O3–MgO–TiO2–SiO2–Ta2O5 by a conventional ceramics method. Effects of Ta2O5 on the phase composition, microstructures, and electrical properties of ZnO linear resistive ceramics were investigated. The results show that doping with appropriate amount of Ta2O5 can refine the grains of the main crystalline phase ZnO and the secondary crystalline phase ZnAl2O4 in terms of microstructure, and also can reduce the grain boundary barrier and optimize the I–V characteristics in terms of electrical properties. In addition, the doping of Ta2O5 can improve the stability of the resistivity , and the impedance frequency indicates that the doping of Ta2O5 makes the sample suitable for high-frequency electric fields. The resistivity of the sample doped with 0.2 mol% Ta2O5 is 56.2 Ω·cm, and this sample has the best grain boundary barrier height, nonlinear coefficient and temperature coefficient of resistance of 0.054 eV, 1.04 and −3.48 × 10−3 °C−1, respectively.

Analyses of defect distributions in ZnO varistors based on the Jonscher’s universal power law and the Dissado–Hill model

The defect distributions in ZnO varistors mixed with Bi2O3, NiO, MnCO3, Co2O3, and SiO2 after doping Sb2O3 were investigated, based on the Jonscher’s universal power law and the Dissado–Hill model. The microstructures were investigated using x-ray diffractometer, scanning electron microscope, energy dispersive spectrometer, and x-ray photoelectron spectrometer. The capacitance–voltage (C–V) method was utilized to obtain the parameters of the double Schottky barrier. The dielectric spectra were analyzed to extract the parameters of defect distribution. The current density–electric field (J–E) characteristics were measured to obtain the parameters of electrical properties. We found that with increasing Sb2O3 content, the ZnO grain size distribution become more homogeneous in the Sb2O3-doped ZnO varistors; the density is decreased; except for less homogeneous , more homogeneous distributions of in the depletion layers and the extrinsic defects at the interfaces are achieved in the Sb2O3-doped ZnO varistors. Therefore, the enhancement in the electrical properties was achieved by doping Sb2O3 due to the increased number of active grain boundaries per unit volume, i.e. the increased breakdown field and nonlinear coefficient, and the decreased leakage current density. The results of this study suggest that the Jonscher’s universal power law and the Dissado–Hill model can be effectively used to analyze defect distributions in varistor ceramics.

ZnO-doped Y2O3 ceramic: A prospective Warm White Light Fluorescent Material

Y2O3 ceramics containing up to 4 at.%Zn2+ were prepared by infiltrating a zinc acetate water solution into a pre-sintered matrix of Y2O3. After pressureless sintering for 2 h at 1400 °C, ZnO grains dispersed in an Y2O3 matrix were identified. The photoluminescence (PL) spectra of the Y2O3:ZnO ceramics exhibit a very broad emission band over the entire visible spectral range with an intensity maximum at about 570−590 nm. The intensity of the PL emission increases with an increasing concentration of additive Zn2+, reaching a maximum between 3 and 4 at.%. The annealing temperature also affects the emission intensity. The Y2O3-ZnO ceramic emits yellowish (warm) white light with the CIE 1931 colour coordinates (0.39,0.43) and a correlated colour temperature in the range of 4000−4600 K. The luminescence decay kinetics at RT exhibit multi-exponential behaviour with faster (∼180 ns) and slower (1.3μs and 8.0μs) decay components and the average lifetime spanning into the range of 5.3–6.5μs.