Photoluminescence Emission Characteristics Research Articles

Observation of broad triangular Frank-type stacking faults and characterization of stacking faults with emission wavelengths below 430 nm in 4H–SiC epitaxial layers

Frank-type stacking faults in 4H–SiC epitaxial layers were investigated using room-temperature photoluminescence mapping and high-angle annular dark-field high-resolution scanning transmission electron microscopy. Remarkably, the intrinsic Frank-type stacking fault (5,2) and intrinsic multilayer Frank-type stacking fault (4,2), which have been reported to have elongated triangular shapes to date, were found to have broader triangular shape, which was typical shape of Shockley-type stacking faults. The shaping of stacking faults could be explained based on the directions of the partial dislocations bounding the stacking faults. Formation models for the intrinsic (5,2) and (4,2) stacking faults were proposed. In addition, we observed Frank-type stacking faults (3,2,2,3) and (3,3) and Shockley-type stacking faults (3,3,3,2,3,2) and (3,2,3,3,3,2), which were not reported before. All of these stacking faults were composed with the stacking numbers 2 and 3 in the Zhdanov notation and showed very close characteristic photoluminescence emission wavelengths of 427–428 nm. Formation models for the stacking faults of (3,2,2,3), (3,3), (3,3,3,2,3,2), and (3,2,3,3,3,2) were proposed, also. Based on the proposed formation models of (4,2) and (3,3) stacking faults, formation models for the Frank-type stacking faults (4,1) and (3,2) were discussed. Finally, we pointed out that the (4,1) Frank-type stacking fault should be the intrinsic not the extrinsic fault, and the (3,2) Frank-type stacking fault is the extrinsic fault.

Novel low temperature synthesis of Y2-x 03 :Eux 3+ nanophosphor prepared by combustion with Thioglycerol as fuel for near UV light emitting diodes (n-UVLEDs).

Luminescent materials used in flat panel displays (FPD), compact fluorescent lamps (CFL), and light-emitting diodes (LEDs) require high purity, uniform particle size, clean surfaces, spherical shape, and dense morphology to ensure long-term stability. Y2 O3 :Eu3+ is a widely studied red phosphor known for its characteristic photoluminescence emission at 613 nm with near-UV excitation at 392 nm. Many synthesis methods have been explored to achieve Y2 O3 :Eu3+ nanoparticles with exceptional purity, consistent phases, and uniform particle sizes. The goal is to obtain particles with pristine surfaces, spherical shape, and compact morphology. This study focuses on the low-temperature synthesis and photoluminescence investigation of Y2-x O3 :Eux 3+ nanophosphors prepared using combustion with thioglycerol as a fuel. The results are compared with Y2-x O3 :Eux 3+ red nanophosphors synthesized using wet chemical and nitrate combustion methods. The photoluminescence characteristics of the Y2-x O3 :Eux 3+ nanophosphors were analyzed using PL emission spectroscopy, XRD, and scanning electron microscopy (SEM). These findings highlight the advantageous properties of the synthesized nanophosphors, such as their suitability for solid-state lighting applications in the lamp industry as highly efficient red phosphors. The combination of high purity, uniform particle size, clean surfaces, spherical shape, and dense morphology contributes to their potential for long-term stability and reliable performance in lighting devices.

White-light luminescence from Tm3+-doped borosilicate glass-ceramics synthesized by the sol-gel route

White-light luminescent Tm3+-doped borosilicate glass-ceramics were synthesized by the sol-gel method. The materials are predominantly amorphous with some embedded nanocrystals of H3BO3 and B2O3 with sizes ranging from 4 to 10 nm, which decrease as the Tm2O3 content is increased. Moreover, the glass transition and crystallization temperatures enhance with the Tm2O3, showing higher thermal stability in the glass-ceramic with 0.50 mol%. Also, the addition of Tm2O3 promotes an increase in the non-bridging oxygen concentration, the occurrence of the boric anomaly, and the incorporation of a higher amount of C species (CC and CO bonds) into the reticular structure of the glass ceramic. Therefore, the optical bandgap reduces (3.62–3.47 eV) while the photoluminescence intensity increases, being maximum at 0.75 mol% of Tm2O3. Interestingly, the luminescent glass-ceramics show a white-emission color, CIE coordinates are (0.31–0.33, 0.33–0.34) instead of those corresponding to blue, which is what usually occurs in other Tm3+-doped materials. This characteristic photoluminescence emission is due to the 1D2→3F4 electronic transitions of Tm3+ ions and the π– π* and n–π* transitions of CC and CO bonds originated by the carbon remnants inside the glass-ceramics. The released white emission has a correlated color temperature of 5600–6650 K, a color rendering index of ∼88, and a quantum yield of 12.3%. These materials are promising candidates for their use as phosphors in solid-state white-light-emitting devices.

Electron–phonon coupling-assisted universal red luminescence of o-phenylenediamine-based carbon dots

Due to the complex core–shell structure and variety of surface functional groups, the photoluminescence (PL) mechanism of carbon dots (CDs) remain unclear. o-Phenylenediamine (oPD), as one of the most common precursors for preparing red emissive CDs, has been extensively studied. Interestingly, most of the red emission CDs based on oPD have similar PL emission characteristics. Herein, we prepared six different oPD-based CDs and found that they had almost the same PL emission and absorption spectra after purification. Structural and spectral characterization indicated that they had similar carbon core structures but different surface polymer shells. Furthermore, single-molecule PL spectroscopy confirmed that the multi-modal emission of those CDs originated from the transitions of different vibrational energy levels of the same PL center in the carbon core. In addition, the phenomenon of “spectral splitting” of single-particle CDs was observed at low temperature, which confirmed these oPD-based CDs were unique materials with properties of both organic molecules and quantum dots. Finally, theoretical calculations revealed their potential polymerization mode and carbon core structure. Moreover, we proposed the PL mechanism of red-emitting CDs based on oPD precursors; that is, the carbon core regulates the PL emission, and the polymer shell regulates the PL intensity. Our work resolves the controversy on the PL mechanism of oPD-based red CDs. These findings provide a general guide for the mechanism exploration and structural analysis of other types of CDs.

Rare-earth-doped electrospun scheelite CaWO4 nanofibers with excitation-dependent photoluminescence and high-linearity cathodoluminescence for ratiometric UV wavelength and radiation sensors

Scheelite structured AWO4 compounds (A = Ba, Ca, Pb and Sr) are efficient hosts for rare-earth dopants. In this work, high-aspect-ratio AWO4 (A = Ba, Ca, Pb and Sr) nanofibers, doped with 5 mol.% Tb and 5 mol.% Eu on A site, were synthesized using a sol-gel electrospinning technique, and their performances as a ratiometric sensor for the detection of UV light wavelength were comparatively studied. High-resolution electron microscopy reveals the presence of nanosized grains composing the nanofibers. The AWO4:5Tb-5Eu nanofibers exhibit strong characteristic photoluminescence (PL) and cathodoluminescence (CL) emission from both Tb3+ and Eu3+ ions. In the case of CaWO4 lattice, the emission intensity ratio of Tb3+/Eu3+ is found to show a linear relationship with the excitation wavelength in the tested range of 240–330 nm, with efficient energy transfer from host lattice to rare-earth ions. However, a similar result is not observed in other scheelite structured BaWO4, PbWO4, and SrWO4 nanofibers. The unique PL emission characteristics of CaWO4:5Tb-5Eu under different UV excitation wavelengths are due to its unique excitation band. This study reveals a potential new application of CaWO4:5Tb-5Eu as a fluorescent probe for UV wavelength detection. Additionally, the CL intensities from CaWO4:5Tb-5Eu nanofibers exhibit highly linear dependences on the applied voltage and current without saturation, which can be utilized for radiation detection.

Facile synthesis of nano-sized zinc-rich ZnCdS ternary alloy and UV-irradiation curing of photoluminescence emission characteristics

Zn-rich ZnCdS nanoparticles (NPs) are successfully synthesized by a facile chemical co-precipitation technique at room temperature. The crystal structure homogeneity of the as-synthesized ternary alloy is examined by the x-ray diffraction pattern and the micro-Raman spectroscopy. The average crystalline domain size is about 4 nm indicating the spatial particle confinement of ternary ZnCdS NPs. The optical bandgap (Eg) of the as-synthesized ZnCdS NPs is 3.95 eV that is higher than the corresponding ternary bulk alloy due to the improvement in the quantum size effect. The effect of UV irradiation on the optical band gap of ZnCdS NPs is investigated at different exposure times. A strong decrease in Eg is observed with increasing exposure time up to 60 min followed by Eg saturation at higher UV exposure times. The as-synthesized ZnCdS nanopowder exhibits a wide emission spectrum extending from UV to visible spectral region, which originating from various intrinsic structural defects. The aging of the as-synthesized ZnCdS nanopowder results in emission intensity quenching without changing peak positions. The emission intensity is recovered by the direct exposure to UV irradiation. This indicates the ability of UV irradiation to cure the emission characteristics of small NPs. This would provide more durability about the emission characteristics of the ZnCdS NPs-based fluorescence sensor.

Role of NH4Cl as Flux on Photoluminescence Properties of Ca1-xZrO3:Eux (x = 0.05) Synthesized by Solution Combustion Route

CaZrO3 ceramics exhibits high chemical, thermal and structural stability. However, its application as a host for various luminophores/activators has not been clearly explored. In present study, CaZrO3 doped with Eu3+, as a potential orange-red phosphor and the effect of NH4Cl as flux during combustion synthesis is investigated. Ca1-xZrO3:Eux (x = 0.05) nanophosphor was prepared through a low temperature, one pot solution combustion synthesis approach using glycine as fuel. Various wt.% of NH4Cl (wt.% = 0, 1, 3, 5, 7) as flux added to the reaction mixture and combustion reaction was performed. X-ray diffraction results showed that the addition of flux has significant effect on the crystallite size and the crystallinity of Ca1-xZrO3:Eux (x = 0.05) phosphor. From SEM morphology, the particles were found to be significantly agglomerated. The extent of agglomeration varies with varying the wt.% of flux. The photoluminescence excitation and emission spectra were recorded under similar condition to evaluate the effect of flux on the optical properties. Interestingly, the amount of flux was found to have significant effect on the photoluminescence emission characteristics. The photoluminescence intensity was found to be the maximum when the flux used was 5 wt.% and further increase in flux amount the photoluminescence intensity decreases. The mechanistic aspects of effect of flux on the photoluminescence were also discussed.

Large open‐circuit voltage boosting of pure sulfide chalcopyrite Cu(In,Ga)S2 prepared using Cu‐deficient metal precursors

AbstractWe performed a comparative study to find out the reasons why it is necessary to prepare the pure sulfide chalcopyrite, Cu(InGa)S2 (CIGS) under a Cu‐deficient condition to improve solar cell performance. It has been shown that CIGS that was grown under Cu‐deficient condition exhibits large open‐circuit voltage (VOC) boosting compared with that the one grown under Cu‐excess condition. Thus, CIGS were prepared from Cu‐excess and Cu‐deficient metal precursor (MP) and characterized concerning the origins of the different VOC. We observed that CIGS prepared using Cu‐excess MP suffered large recombination at buffer/CIGS interface and in bulk, which resulted in serious limitation of the VOC. On the other hand, CIGS prepared from Cu‐deficient MP exhibited largely improved VOC with reduced recombination. We conducted defect analysis using the photoluminescence (PL) method, and CIGS prepared using Cu‐excess MP exhibited strong deep emissions. However, CIGS prepared from Cu‐deficient MP exhibited PL emission characteristics without deep level transition. This implies that a large number of deep level defects exist in the CIGS prepared using Cu‐excess MP, and this might be the reason for the large recombination limiting VOC of the device. Finally, we also present the reason for deep levels in the CIGS prepared using Cu‐excess MP.

Characterization of 4H- and 6H-Like Stacking Faults in Cross Section of 3C-SiC Epitaxial Layer by Room-Temperature μ-Photoluminescence and μ-Raman Analysis.

We report a comprehensive investigation on stacking faults (SFs) in the 3C-SiC cross-section epilayer. 3C-SiC growth was performed in a horizontal hot-wall chemical vapour deposition (CVD) reactor. After the growth (85 microns thick), the silicon substrate was completely melted inside the CVD chamber, obtaining free-standing 4 inch wafers. A structural characterization and distribution of SFs was performed by μ-Raman spectroscopy and room-temperature μ-photoluminescence. Two kinds of SFs, 4H-like and 6H-like, were identified near the removed silicon interface. Each kind of SFs shows a characteristic photoluminescence emission of the 4H-SiC and 6H-SiC located at 393 and 425 nm, respectively. 4H-like and 6H-like SFs show different distribution along film thickness. The reported results were discussed in relation with the experimental data and theoretical models present in the literature.

Synthesis and characterization of well-dispersed amorphous LnBO3·3H2O (Ln: Dy, Tb) nanoparticles

Lanthanide nanoborates (LnBO3·3H2O (Ln: Dy, Tb)) were prepared in the presence of polyethylene glycol (PEG) using a buffered-precipitation method. The same procedure was performed without adding PEG to expose the chemical formulations of the samples. X-ray diffraction (XRD), thermal gravimetric analysis (TGA), Fourier transform infrared spectrum (FTIR) strongly supported amorphous lanthanide orthoborates having LnBO3·3H2O structure. From TEM images, the mean particle size and standard deviation for Dy and Tb were calculated as 15.2 ± 6.3 nm and 15.4 ± 6.1 nm, respectively. The percentages of PEG molecules in the samples were determined as 7.5% for Dy and 4.31% for Tb by TGA. The average hydrodynamic sizes and surface charges of DyBO3·3H2O and TbBO3·3H2O nanoparticles in the distilled water were measured as 150.7 nm (PDI 0.152) + 40.9 ± 8.8 mV and 151.3 nm (PDI 0.105) + 41.9 ± 6.8 mV, respectively. The energy band gaps of both lanthanide nanoborates were determined as 5.3 eV by applying the Kubelka–Munk function to the measured UV–Vis diffuse reflectance spectra. The amorphous DyBO3·3H2O and TbBO3·3H2O nanoparticles exhibited strong paramagnetic behavior with μeff/μB values of 8.57 for Dy and 8.73 for Tb, respectively, at room temperature. The characteristic photoluminescence emission corresponding to the transition from 5D4, 5D4 and 5D4 excited states to 7Fj (j = 6, 5, 4, 3, 2, 1, 0) of the Tb+3 ions was observed in the wavelength range of 370–700 nm. Similarly, the emission spectrum of Dy+3 ions composed of peaks of different strength extends in the wavelength range of 370–850 nm. Although the emission peaks were found to be nearly temperature independent for both samples, the normalized integrated intensity of full spectrum corresponding to TbBO3·3H2O sample decreased by %25, and increased by %10 for DyBO3·3H2O over the temperature range of 10–300 K.

Characterization of luminescence properties of exfoliated mica via sonication technique

Two-dimensional single- and/or multi-layered mica exfoliated from original bulk mica are fabricated via a simple sonication technique. At 298 K, the photoluminescence spectra of nano-sized mica reveal green emission in the region of approximately 516 nm, while the spectra of bulk mica do not exhibit photoluminescence characteristics. However, at 70 K, it is observed that both nano-sized and bulk mica have slightly similar photoluminescence emission characteristics. Here, in contrast to the conventional energy bandgap generally increasing at the nano-size, muscovite-type mica exhibits a phenomenon in which the energy bandgap becomes narrower as a mono-layer develops owing to frequent lattice relaxations.

Growth of thiophene based oligomers using Stille and direct arylation methods for optoelectronic applications

Palladium catalyzed Stille coupling reactions are extensively used for the preparation of functionalised thiophene based polymers. In addition, polycondensation via direct C-H arylation produces alternating copolymers in moderate yields. In the present work, we report the synthesis and optoelectronic properties of thiophene based compounds having rigid cycloalkanone and a novel hexhydro-2H-indazole spacers in between. X-ray diffraction analysis shows the semi-crystalline nature of the synthesized materials with extensive side chain crystallinity. Band-gap energy of the synthesized materials has been obtained experimentally via optical and electrochemical methods and theoretically via computational studies. Open aperture Z-Scan results confirm the competence of these materials as optical limiters (NLO) while the photoluminescence emission characteristics and Schottky diode characteristics indicate their application prospects in Polymer Light Emitting Diodes (PLEDs). Polymers having hexhydro-2H-indazole spacers appear to be promising candidates for optoelectronic applications.

Cathodo- and photoluminescence emission of a natural Mg-Cr carbonate layered double hydroxide

Abstract Spectral emission of a natural layered double hydroxide (LDH) studied by cathodo- and photoluminescence (PL), displays complex glow curves with wavebands that could be attributable to (i) the paramagnetic Non-bridging Oxygen Hole Center defects (peaked at 330 nm), (ii) F o centers (oxygen vacancies trapping two electrons) associated with O vacancy-hole centers and Me–O bonding defects and dehydroxylation process (in the range of 360–500 nm), (iii) presence of Mn 2+ (0.15%) substituting Mg 2+ ions (530–640 nm) and (iv) a red-IR band mainly associated with Cr and Fe point defects. The presence of Cr 3+ ion activators induces characteristic PL emission peaks in the red-infrared region at 681, 688 and 696 nm linked to 2 E → 4 A 2 transitions. The sample (Mg 6 Cr 2 CO 3 (OH) 16 ·4H 2 O) previously characterized by environmental scanning electron microscope, X-ray diffraction, and X-ray fluorescence indicates that this natural hydrotalcite-like compound is associated with hydroxyl-rich silicates (nimite and clinochlore) and Mg-Fe carbonate and Ni-Fe carbonate LDH (pyroaurite and reevesite).

Effect of capping procedure on quantum dot morphology: Implications on optical properties and efficiency of InAs/GaAs quantum dot solar cells

InAs/GaAs quantum dot solar cell structures have been grown by metal organic vapor phase epitaxy, using partial capping of the quantum dots plus a subsequent thermal anneal. The optical characteristics of the InAs quantum dot layers have been studied as a function of the GaAs capping layer thickness and annealing temperature. We observe that a thinner capping layer and a higher annealing temperature result in lower non-radiative defect density and in improved quantum dot size homogeneity, leading to intense and sharp photoluminescence emission at low temperatures. We use an effective mass approximation model to correlate the photoluminescence emission characteristics to the quantum dot composition and dimensions. The resulting InAs/GaAs intermediate band solar cells show the best performance for the case of a 3 nm thick capping layer and annealing at 700 °C.

Core-shell structured NaYF4:Yb,Tm@CdS composite for enhanced photocatalytic properties.

NaYF4:Yb,Tm upconversion nanocrystals with hexagonal structure possess excellent photoluminescence emission characteristics. Under near infrared (NIR) light irradiation, the Yb3+ ions act as sensitizers to absorb the NIR light and transform NIR light into ultraviolet (UV) and visible (Vis) light continuously. Hybrid NIR-activated photocatalysts can be fabricated by combining upconversion nanocrystals with various semiconductor nanocrystals. In this paper, NaYF4:Yb,Tm micro-rods were hydrothermally synthesized with oleic acid as capping ligand. The NaYF4:Yb,Tm@CdS composite was fabricated by in situ generation of CdS nanoclusters on the surface of NaYF4:Yb,Tm micro-rods. The morphologies and structures of NaY4:Yb,Tm and NaYF4:Yb,Tm@CdS were characterized by XRD, SEM, TEM, XPS, UV-Vis and PL spectroscopy. The results of photocatalytic experiments indicated that the NaYF4:Yb,Tm@CdS composite displayed photocatalytic activity under NIR irradiation. In comparison with pure CdS, the photocatalytic ability of NaYF4:Yb,Tm@CdS composite under Vis-NIR irradiation was obviously enhanced. 82% of RhB was degraded by NaYF4:Yb,Tm@CdS catalyst within 75 min under Vis-NIR irradiation, which was more effective than pure CdS (65% degradation of RhB).

Solvatochromism in highly luminescent environmental friendly carbon quantum dots for sensing applications: Conversion of bio-waste into bio-asset

Recently studies on synthesis and fluorescence based sensing in biocompatible carbon quantum dots (CQDs) have become a widely spoken topic of research due to the several advantageous properties of CQDs in compared to semiconductor quantum dots. In this work, we have reported the rarely reported solvatochromism along-with a high photoluminescence (PL) quantum yield (PLQY) of 22%. Samples have been synthesized by using a simple process of hydrothermal carbonization of a naturally occurring bio-waste i.e. Aegle marmelos leaves powder. The linear absorption and PL emission characteristics of CQDs have been studied in different solvent environments to explore the origin of the observed excitation dependent PL emissions characteristics of the sample. The interesting solvatochromic PL (SPL) behavior of CQDs are observed at an excitation wavelength of 325nm by dispersing them in different polar protic and aprotic solvents, which suggest their possible applications as a replacement of solvatochromic dye molecules for sensing applications. Different polarity functions and molecular-microscopic solvent polarity parameter (ETN) are used to calculate the change in dipole moment (Δδ) of the solute-solvent system and the origin of SPL in CQDs has been explained. The SPL behavior of CQDs has been utilized for fluorescence sensing of organic liquids (Ethanol and Tetrahydrofuran) in water. Whereas, the photo-induced electron transfer mediated quenching in PL of aqueous dispersion of CQDs has led to development of “turn off” fluorescence Fe3+ ion sensor with a detection limit of 0.12μM. Therefore, this work may open a new avenue of conversion of a bio-waste into a fluorescent bio-asset.

Luminescent properties of Tb doped gadolinium aluminate nanophosphors for display and forensic applications

Abstract A novel green light emitting GdAlO3:Tb3+ (1–11 mol%) nanophosphor has been synthesized by the solution combustion method and the final products were characterized. The energy band gap of the samples was estimated in the range of 5.13–5.88 eV from diffuse reflectance spectra. The effect of the added Tb3+ ions on the electronic structure was considered based on the absolute electronegativity. The characteristic photoluminescence emission corresponding to the transition 5D4→7Fj (j = 6, 5, 4, 3) of the Tb3+ ions was observed in the wavelength range of 500–650 nm, and assigned due to the f–f transitions upon the 378 nm excitation. The optimized nanophosphor was found suitable for applications in the latent fingerprint detection. The photometric characterization has revealed the excellent color chromaticity coordinates and the correlated color temperature levels. They are on the same level of commercial phosphors and quite useful for green WLEDs, solid state displays and forensic applications as well.

Effect of defects on quantum yield in blue emitting photoluminescent nitrogen doped graphene quantum dots

This paper presents a comprehensive study of the impact of defects on quantum yield in Nitrogen doped graphene quantum dots (N-GQDs). The facile and high yielding hydrothermal method was used to process the N-GQDs by selecting two different nitrogen containing powders, that is, NH4Cl (sample-I) and (NH4)2SO4(sample-II). Initially, the synthesized samples were characterized by using High Resolution Transmission Electron Microscope (HRTEM), Powdered X-Ray Diffraction, Raman Spectroscopy, and UV-Visible spectroscopy, Fourier Transform Infrared Spectroscopy, and Photoluminescence (PL) for sample integrity. HRTEM images suggest that the majority of the both sample types were in the narrow range of 5–20 nm in diameter. The samples show blue photoluminescence and excitation dependent PL emission characteristics. As expected, by using the different excitation energy in PL, appearance of peak introduces additional energy levels between π and π* that provide alternative electron transition pathways. The most remarkable finding is that the fluorescence quantum yield is up to 28% for sample-I and is 49.8% for sample-II, which is higher than that of reported GQDs (less than 25%). This clearly suggests that the defect states related to Nitrogen, Chlorine, and Sulfur that alter the band gap of the GQDs determine the PL characteristics and the quantum yield.

Temperature dependence of the energy bandgap of multi-layer hexagonal boron nitride

The temperature dependence of the energy bandgap of hexagonal boron nitride (h-BN) has been probed via photoluminescence emission characteristics of a donor-to-acceptor pair transition in a 20-layer h-BN epilayer. The results indicate that the universal behavior of bandgap decreasing with temperature is absent in multi-layer h-BN. Below 100 K, the bandgap energy variation with temperature, Eg vs. T, is dominated by the electron-phonon coupling and conforms to the common behavior of redshift with an increase in temperature. At T > 100 K, the bandgap shows an unusual blueshift with temperature, which can be attributed to the unique behavior of the in-plane thermal expansion coefficient of h-BN that becomes negative above around 60 K. Although both graphite and h-BN have negative thermal expansion coefficients in a broad temperature range, graphite has a zero energy bandgap, which makes h-BN a unique semiconductor to exhibit this unusual temperature dependence of the energy bandgap.

On the potential of Er-doped AlN film as luminescence sensing layer for multilayer Al/AlN coating health monitoring

Luminescence sensing is an attractive approach for in-situ monitoring the health and integrity of multilayered surface protective coatings on highly active metals. In this work, we demonstrate the potential of erbium (Er) doped aluminum nitride (AlN) films to be applied as luminescence sensing layer in the Al/AlN multilayered coating system. The AlN:Er films were prepared by radio-frequency magnetron sputtering from Al targets doped with varied concentrations (from 0.5 at.% to 2.5 at.%) of Er. The chemical composition, surface morphology, crystal structure, chemical state and optical properties of the deposited AlN:Er films were investigated. We found that the crystal structure, surface roughness and optical properties of the AlN:Er films have strong correlations with the Er doping level. The as-deposited AlN:Er films showed the characteristic photoluminescence emission lines of the trivalent Er ions in the visible frequency range and quenching was observed when the Er doping level increased to 2.5 at.%. This work signifies the viability of AlN:Er film as luminescence sensing layer and the optimal Er doping concentration of the Al sputtering target is 2.0 at.% for practical applications.