Pulsed Laser Research Articles

Structural features of steel pulsed laser treatment within a permanent magnetic field

Structural features of steel pulsed laser treatment within a permanent magnetic field

Novel Class of Crystal/Glass Ultrafine Nanolaminates with Large and Tunable Mechanical Properties.

The control of local heterogeneities in metallic glasses (MGs) represents an emerging field to improve their plasticity, preventing the propagation of catastrophic shear bands (SBs) responsible for the macroscopically brittle failure. To date, a nanoengineered approach aimed at finely tuning local heterogeneities controlling SB nucleation and propagation is still missing, hindering the potential to develop MGs with large and tunable strength/ductility balance and controlled deformation behavior. In this work, we exploited the potential of pulsed laser deposition (PLD) to synthesize a novel class of crystal/glass ultrafine nanolaminates (U-NLs) in which a ∼4 nm thick crystalline Al separates 6 and 9 nm thick Zr50Cu50 glass nanolayers, while reporting a high density of sharp interfaces and large chemical intermixing. In addition, we tune the morphology by synthesizing compact and nanogranular U-NLs, exploiting, respectively, atom-by-atom or cluster-assembled growth regimes. For compact U-NLs, we report high mass density (∼8.35 g/cm3) and enhanced and tunable mechanical behavior, reaching maximum values of hardness and yield strength of up to 9.3 and 3.6 GPa, respectively. In addition, we show up to 3.6% homogeneous elastoplastic deformation in compression as a result of SB blocking by the Al-rich sublayers. On the other hand, nanogranular U-NLs exhibit slightly lower yield strength (3.4 GPa) in combination with enhanced elastoplastic deformation (∼6%) followed by the formation of superficial SBs, which are not percolative even at deformations exceeding 15%, as a result of the larger free volume content within the cluster-assembled structure and the presence of crystal/glass nanointerfaces, enabling to accommodate SB events. Overall, we show how PLD enables the synthesis of crystal/glass U-NLs with ultimate control of local heterogeneities down to the atomic scale, providing new nanoengineered strategies capable of deep control of the deformation behavior, surpassing traditional trade-off between strength and ductility. Our approach can be extended to other combinations of metallic materials with clear interest for industrial applications such as structural coatings and microelectronics (MEMS and NEMS).

Corrosion and oxidation behaviors of CoAlTiWTa RHEA coating on Inconel 718 superalloy prepared by laser cladding

CoAlTiWTa refractory high-entropy alloy (RHEA) coating was prepared on Inconel 718 superalloy by pulsed laser cladding. Corrosion behavior in 3.5 wt% NaCl solution at room temperature and oxidation behavior at 600 ℃ of the coating were systematically investigated. The electrochemical performance, surface morphology, and corrosion and oxidation products were carefully characterized. The results show that the RHEA coating has a higher corrosion potential, smaller corrosion current, higher resistance value, and a more obvious passivation effect. Duplex-layer oxide film composed of an internal Al2O3-TiO2 layer and an external Co oxide layer is formed on the RHEA coating, improving high-temperature oxidation resistance.

Tunable charge transport properties in non-stoichiometric SrIrO3 thin films.

Delving into the intricate interplay between spin-orbit coupling and Coulomb correlations in strongly correlated oxides, particularly perovskite compounds, has unveiled a rich landscape of exotic phenomena ranging from unconventional superconductivity to the emergence of topological phases. In this study, we have employed pulsed laser deposition (PLD) technique to grow SrIrO3 (SIO) thin films on SrTiO3 substrates, systematically varying the oxygen content during the post-deposition annealing. X-ray Photoelectron Spectroscopy (XPS) provided insights into the stoichiometry and spin-orbit splitting energy of Iridium within the SIO film, while high-resolution X-ray studies meticulously examined the structural integrity of the thin films. Remarkably, our findings indicate a decrease in the metallicity of SIO thin films with reduced annealing O2 partial pressure. Furthermore, we carried out magneto-transport studies on the SIO thin films, the results revealed intriguing insights into spin transport as a function of oxygen content. The tunability of the electronic band structure of SrIrO3 films with varying oxygen vacancy is correlated with the DFT calculations. Our findings elucidate the intricate mechanisms dictating spin transport properties in SrIrO3 thin films, offering invaluable guidance for the design and optimization of spintronic devices based on complex oxide materials. Notably, the ability to tune bandwidth by varying post-annealing oxygen partial pressure in iridate-based spintronic materials holds significant promise for advancing technological applications in the spintronics domain.&#xD.

Picosecond Imaging Of Bubbly Flows

Despite their ubiquity, bubbly flows are notoriously challenging to instrument. In high-void fractions, most optical measurement techniques fail due to intense scattering and occlusion. Ultrafast imaging with picosecond exposure times offers an opportunity, allowing measurements before scattering obscures the field of view. Furthermore, detecting the time of arrival of photons allows measurement of bubble sizes, even for those partially occluded. Through implementing the Optical Kerr Effect (OKE), using a 70 fs 800 nm pulsed laser and a Carbon Disulfide cell, images are acquired with an exposure of 2.9 ps. Gating these images with an optical delay stage further allows the decomposition of scenes with 33 fs time increments. Proof of concept is demonstrated by applying this approach to static scenes of submerged bubbles at low and high void fractions. The experimental temporal decomposition shows the arrival of photons that travel through different media (air, water, and glass) and those scattered within the turbid media. A new visualization is presented to display this breakdown concisely, the Temporally Tagged Shadowgraph (TTS), presenting the time of arrival with the context of position and surroundings. Bubble sizes are measured using this temporal information and through edge detection, with good agreement for single unoccluded bubbles. With polydisperse bubble plumes, time delay-based measurements tend to overestimate bubble diameter; however, this could also be due to greater uncertainty in edge detection with occlusion. This demonstrates the potential of Ultrafast Imaging when it comes to probing high-void fraction flows. By further shortening exposure times and improving the robustness of processing algorithms, the scope of applicability of this technique can be widened.

Near-Wall Flow Features In ZPG-TBL At Various Reynolds Numbers Using Dense 3D Lagrangian Particle Tracking

The 3D Lagrangian particle tracking method Shake-The-Box (STB) and, subsequently, the data assimilation method FlowFit3 have been applied to measure the flow field in a narrow wall-parallel volume inside the nearwall region of a zero-pressure-gradient (ZPG) turbulent boundary layer (TBL) flow at various Reynolds numbers. The STB experiments have been conducted in the 1m- wind tunnel facility of DLR in Göttingen at relatively high particle image densities (~0.07 ppp) using µm-sized DEHS particles and high-repetition pulse laser at up to 38.1 kHz. The results show that the chosen methodology is able to volumetrically resolve almost all features of the flow inside the viscous sub-, buffer- and lower logarithmic- layer in space and time at Reynolds numbers up to Re θ = 5,455. The gained data consists of time-series of spatially well resolved 3D velocity, acceleration and pressure fields, as well as a huge amount of long Lagrangian particle trajectories. Selecting the viscous sublayer part of the measurement volume provides time-series of the 2D distribution of both components of the instantaneous wall-shear stresses w,x/z . The resulting data are used for conditional and time-resolved 3D analyses of coherent structures, rare (e.g. back flow) events and two-point space-timecorrelations.

Towards Time-Resolved Multi-Property Measurements By Single-Frequency FRS

The filtered Rayleigh scattering technique (FRS), extended by the method of frequency scanning, has historically been limited to time-averaged multi-property flow measurements. In our recently published work, we present a concept that potentially enables the combined measurement of time-resolved pressure, temperature and three-component (3C) velocity fields. It is based on the observation of the region of interest from six perspectives and a single excitation frequency. This work summarizes and expands on a follow-up publication that experimentally verifies this concept on an aspirated circular duct flow. For this purpose, the results obtained from single-frequency data processing are compared with reference pressures, temperatures and corresponding LDA velocity measurements. Overall, a very good agreement is found for all operating points with accuracies of 3.4% in pressure, 1.3% in temperature and ±2 m/s in axial velocity. Concerning precision, a newly developed multistage evaluation procedure enables values for pressure, temperature and velocity as low as 3 hPa, 2.2 K and 1.7 m/s. In a second flow configuration, an axial swirler is introduced into the duct. The resulting secondary flow structure and deformation of the axial velocity field caused by swirler geometry and support are very well captured with the single-frequency analysis. A closing discussion on the implementation challenges of a single-frequency multi-property FRS instrument with pulsed laser radiation reveals significant obstacles to overcome. Due the considerable optimization potential identified, chances are high that true time-resolved multi-property measurements by FRS will become a reality.

Pulsed laser deposition and structural analysis of Ba2Ti6O13 epitaxial thin film on the (210) surface of SrTiO3 single crystal

Abstract A single crystalline thin film of Ba2Ti6O13 was grown on the (210) surface of a SrTiO3 single-crystal substrate by pulsed laser deposition. Scanning transmission electron microscopy shows that the Ba2Ti6O13 thin film grew epitaxially with the a-plane, and the b-/c-axes of Ba2Ti6O13 parallel to the (210) plane and the [00-1]/[-120] directions of SrTiO3, respectively. The electrical conductance of the Ba2Ti6O13 film was approximately one order larger than that of reduced SrTiO3-δ single crystal with oxygen deficiency of roughly δ = 0.05. Electronic structure calculations predict that δ is an n-type degenerate semiconductor with spin-split states primarily of Ti 3d orbital.

High‐Speed and Long‐Distance Spin‐Wave Propagation in Spinel γ‐Fe2O3 Epitaxial Thin Films

AbstractIn spin wave (SW) devices, the modulation of SWs for computational units is necessary, imposing extremely high demands on material systems. In this study, high‐quality epitaxial‐grown spinel γ‐Fe2O3 thin films on conductive Nb‐doped SrTiO3 substrates, achieving fast‐speed, high‐frequency, and long‐distance SW propagation in this ferrimagnetic material, are developed. A novel two‐step film growth technique using pulsed laser deposition is proposed and optimized, and the damping constant, exchange stiffness, and anisotropies of γ‐Fe2O3 are determined. Compared to reported semiconductor magnetic materials, these epitaxial‐grown γ‐Fe2O3 thin films exhibit a significantly lower damping constant of 10−2, representing a substantial advancement. Using finite‐difference calculations, SW propagation is simulated, and vital information on transmission distance and dispersion curves is obtained. Experimental results show excellent agreement with these simulations. By applying a voltage to both sides of the conducting substrate, current across the film and SW device, resulting in the frequency shift of the SWs, is generated. These results demonstrate that high‐quality γ‐Fe2O3 films developed through the two‐step growth method can efficiently propagate SWs, offering possibilities for various modulation methods in SW‐based computing devices. This study positions spinel γ‐Fe2O3 as a promising ferrimagnetic candidate for future applications in efficient SW modulation within computational systems.

Ballistic-aggregated Carbon Nanofoam in Target-side of Pulsed Laser Deposition for Energy Storage Applications.

In pulsed laser deposition, along the traditionally exploited deposition on the front-side of the plasma-plume, a coating forms on the surface of the target as well. For reproducibility, this residue is usually cleaned and discarded. Here we instead investigate the target-side coated materials and employ them as a binder-free supercapacitor electrode. The ballistic-aggregated, target-side nanofoam is compact and features a larger fraction of sp2-carbon, higher nitrogen content with higher graphitic-N and lower oxygen content with fewer COOH groups than that of diffusive-aggregated conventional nanofoams. They are highly hydrogenated graphite-like amorphous carbon and superhydrophilic. The resulting symmetric micro-supercapacitor delivers higher volumetric capacitance of 522 mF/cm3 at 100 mV/s and 104% retention after 10000 charge-discharge cycles over conventional nanofoam (215 mF/cm3 and 85% retention) with an areal capacitance of 134 μF/cm2 at 120 Hz and ultrafast frequency response. Utilizing the normally discarded target-side material can therefore enable high performing devices while reducing waste, cost and energy input per usable product. leading towards a greater sustainability on nanomaterials synthesis and deposition techniques.

New Fe3O4-Based Coatings with Enhanced Anti-Biofilm Activity for Medical Devices

With the increasing use of invasive, interventional, indwelling, and implanted medical devices, healthcare-associated infections caused by pathogenic biofilms have become a major cause of morbidity and mortality. Herein, we present the fabrication, characterization, and in vitro evaluation of biocompatibility and anti-biofilm properties of new coatings based on Fe3O4 nanoparticles (NPs) loaded with usnic acid (UA) and ceftriaxone (CEF). Sodium lauryl sulfate (SLS) was employed as a stabilizer and modulator of the polarity, dispersibility, shape, and anti-biofilm properties of the magnetite nanoparticles. The resulting Fe3O4 functionalized NPs, namely Fe3O4@SLS, Fe3O4@SLS/UA, and Fe3O4@SLS/CEF, respectively, were prepared by co-precipitation method and fully characterized by XRD, TEM, SAED, SEM, FTIR, and TGA. They were further used to produce nanostructured coatings by matrix-assisted pulsed laser evaporation (MAPLE) technique. The biocompatibility of the coatings was assessed by measuring the cell viability, lactate dehydrogenase release, and nitric oxide level in the culture medium and by evaluating the actin cytoskeleton morphology of murine pre-osteoblasts. All prepared nanostructured coatings exhibited good biocompatibility. Biofilm growth inhibition ability was tested at 24 h and 48 h against Staphylococcus aureus and Pseudomonas aeruginosa as representative models for Gram-positive and Gram-negative bacteria. The coatings demonstrated good biocompatibility, promoting osteoblast adhesion, migration, and growth without significant impact on cell viability or morphology, highlighting their potential for developing safe and effective antibacterial surfaces.

Surface plasmonic Au nanoparticles assisted CuO nanorods for broadband diverse ultrafast pulse generation

In virtue of the local surface plasmon resonance (LSPR) properties of metal nanoparticles to enhance the nonlinear optical response of the material, we successfully embed small-size Au nanoparticles into CuO nanorods. Then, theoretical and experimental methods verify that the assistance of ultrafast plasma response enhances the light-matter interaction. The LSPR characteristics and evanescent field distribution of the Au-CuO saturable absorber on the tapered fiber are studied by the finite element simulation method (FEM). By utilizing the Z-scan technology and twin-balanced detector system, excellent nonlinear optical (NLO) properties of the Au-CuO nanorods are demonstrated. Subsequently, depending on the remarkable nonlinear saturable absorption effect of Au-CuO, multiple operating states such as Q-switched, conventional soliton, double-subpulse soliton cluster, and noise-like pulse mode-locking are achieved in the erbium-doped fiber ring cavity at 1.5 μm. In addition, dual-wavelength mode-locking pulses with the center wavelengths of 1031 nm and 1035 nm are realized in the ytterbium-doped fiber ring cavity. This work describes an effective strategy to improve the NLO properties of CuO nanorods and indicates the great potential of Au-CuO in pulsed fiber lasers, opening a path for its application in ultrafast photonics and optoelectronics.

Broadband flat supercontinuum generated by chalcogenide double-clad step-index fiber with special dispersion

Abstract To achave a broader supercontinuum in the mid-infrared band, a chalcogenide double-clad step-index fiber is proposed. Comprising As2Se3, AsSe2, and As2S5 glass, this fiber effectively confines light within the core, minimizing fiber dispersion fluctuations. By iteratively adjusting the dispersion curve of the fiber, enhancement of the supercontinuum spectrum generation is possible. Spectral broadening primarily results from four-wave mixing and self-phase modulation. Raman scattering within the pulse generates unstable higher-order solitons, which, upon breakup, contribute to spectrum broadening. This study explores the effects of pulse laser parameters and fiber length on supercontinuum generation, obtains regular cognition and offers theoretical analyses of the results. Through optimization of parameters, a mid-infrared supercontinuum with an 11 μm width is achieved. These findings underscore the potential of chalcogenide double-clad step-index fiber for generating a mid-infrared supercontinuum light source. The designed fiber structure should be helpful in supercontinuum sources, bio-molecule sensing, and spectroscopy.

Design of a three-frequency Rayleigh lidar for simultaneous temperature and wind measurements

This study proposes what we believe to be a novel high-spectral-resolution three-frequency Rayleigh lidar for simultaneously measuring middle atmosphere temperature and wind. The temperature and wind could be retrieved without assuming an external reference temperature, as typical for a traditional Rayleigh Doppler lidar. Adopting a similar idea used in sodium temperature/wind lidar, this system alternatively emits laser pulses at three frequencies. It receives the corresponding Rayleigh backscattered signals filtered by an iodine cell as a frequency discriminator. The three frequencies are optimized based on the spectral characteristics resulting from the convolution of the pulse laser lineshape convolved Rayleigh scattering signal with iodine molecular absorption spectrum. A two-dimensional calibration curve for temperature and wind ratio is then generated from the theoretical calculation of the final convoluted spectra and used to retrieve temperature and wind simultaneously. Simulated with the return signals collected by a current broadband Rayleigh lidar (30-inch telescope and 15 W output laser power), the temperature and wind uncertainties with resolutions of 1 km and 1 hr are estimated to be 0.4 K and 0.35 m/s, respectively, at 30 km and increase to 16.3 K and 8.1 m/s at 70 km.

Deciphering the Nd3+ environment and energy-transfer mechanisms in thermally stable novel calcium aluminate glasses: elucidation of broadband high-gain performance for laser applications

Rare-earth-doped barium calcium aluminate (BCA) glasses, having extended infrared (IR) transmission (6 μm), are attractive materials for near IR (NIR) photonic applications. Nd2O3-doped BCA glasses display broadband emission at 1.07 µm, but they are limited, with poor glass-forming ability (GFA) and low emission cross sections. In the present study, four different barium zinc calcium aluminate (BZCA) glasses are synthesized with varied ZnO concentrations (from 9.5 to 24.5 mol%) and doped with 0.5 mol% Nd2O3 to decipher the effect on GFA and spectroscopic properties. The addition of ZnO enhances the GFA, and the NdBZCA20 glass shows the maximum GFA. Ultraviolet (UV)–visible (Vis)–NIR absorption spectra reveal a decreasing trend in the nephelauxetic effect, while J–O parameters, emission, and gain properties lead to no significant alteration with increasing ZnO, and the structure–properties correlation is established accordingly. However, the emission cross sections for all ZnO concentrations are found ∼4.5 × 10−20 cm2 accompanied by broadband emission (Δλ eff ∼ 40 nm), which ensures the potentiality of these glasses for low-threshold high-gain laser applications as well as ultrashort pulse laser applications. Furthermore, a thorough analysis of 1.06 µm emission as a function of Nd concentration in the BZCA20 glass is reported here. The emission spectra and decay time indicate that 0.5 mol% is the optimized doping concentration. Inokuti–Hirayama and Burshtein equations are adopted to study the decay kinetics and energy-transfer mechanisms, which confirm that the energy-transfer process due to cross-relaxation is dominant up to 0.5 mol% concentration, whereas, beyond that concentration, excitation energy migration via the hopping mechanism supersedes.

Investigation of Single Grain Grinding of Titanium Alloy Using Diamond Abrasive Grain with Positive Rake Angle

Traditional grinding, which is predominantly performed with a negative rake angle (NRA), can be transformed into grinding with a positive rake angle (PRA) by employing femtosecond pulsed laser technology to modify the apex angle of the grains to be less than 90°. This innovative approach aims to reduce grinding forces and grinding temperatures while improving the surface quality of typical hard-to-machine materials. To assess the performance of PRA single grain grinding and to investigate the underlying mechanisms, the finite element simulation software ABAQUS 6.14 was employed to model the grinding of Ti6Al4V titanium alloy with a single diamond abrasive grain. The dependence of grinding force and temperature in single grain grinding with a PRA or an NRA under different grinding parameters was studied and compared. PRA and NRA single diamond grain grinding experiments on Ti6Al4V alloy were carried out, with grinding forces measured using a dynamometer and compared with the simulation results. The grinding surface morphology and surface roughness were observed and measured, and a comparison was made between PRA and NRA grinding. The results indicated that in single diamond grain grinding, transforming to a PRA significantly enhances grinding performance, as evidenced by reduced grinding forces, lower temperatures, improved surface morphology, and decreased surface roughness. These findings suggest that PRA single diamond grain grinding offers substantial benefits for the precision machining of hard-to-machine materials, marking a step forward in optimizing surface finishes.

Pulsed laser induced plasma and thermal effects on molybdenum carbide for dry reforming of methane

Dry reforming of methane (DRM) is a highly endothermic process, with its development hindered by the harsh thermocatalytic conditions required. We propose an innovative DRM approach utilizing a 16 W pulsed laser in combination with a cost-effective Mo2C catalyst, enabling DRM under milder conditions. The pulsed laser serves a dual function by inducing localized high temperatures and generating *CH plasma on the Mo2C surface. This activates CH4 and CO2, significantly accelerating the DRM reaction. Notably, the laser directly generates *CH plasma from CH4 through thermionic emission and cascade ionization, bypassing the traditional step-by-step dehydrogenation process and eliminating the rate-limiting step of methane cracking. This method maintains a carbon-oxygen balanced environment, thus preventing the deactivation of the Mo2C catalyst due to CO2 oxidation. The laser-catalytic DRM achieves high yields of H2 (14300.8 mmol h−1 g−1) and CO (14949.9 mmol h−1 g−1) with satisfactory energy efficiency (0.98 mmol kJ−1), providing a promising alternative for high-energy-consuming catalytic systems.

Laser Powder Bed Fusion and Heat Treatment of the Martensitic Age‐Hardenable Steel (1.2709)

The primary objective of this study is to clarify the fundamental question of whether, in principle, it is possible to dispense with a prior solution annealing process in favor of a direct aging heat treatment for specimens of maraging stainless steel grade X3NiCoMoTi18‐9‐5 (1.2709) produced by laser powder bed fusion (LPBF). The waiver of a solution annealing process would significantly increase the process efficiency and thus support a sustainable and resource‐friendly production of such components. Therefore, the hardness, microstructure, and the present phases of specimens in as‐built + aged condition (AB + A) and solution‐annealed + aged (SOL + A) are examined during this study. Initially, an extended parameter study is performed using a Renishaw AM 250 LPBF system equipped with a pulsed mode laser system to achieve the highest possible apparent density. As test specimens, small cubes are produced for parameter study and are analyzed for porosity by means of optical microscopy. To investigate the relationship between microstructure and hardness in different material states, one series of specimens is aged directly after LPBF processing in the as‐built state (AB + A). For comparison, the other series was solution annealed at 820 °C for 60 min, quenched in water and then aged (SOL + A). A maximum hardness value of 614 HV1.0 is achieved for specimen aged at 490 °C for 120 min in as built condition (AB + A), while 624 HV1.0 was measured for specimen aged at 490 °C for 180 min in conventionally solution annealed + aged (SOL + A) condition. Significant austenite reversion is not observed at aging temperature of 490 °C in both cases. Aging of specimens at temperatures of 540 and 600 °C resulted in reduction of specimen hardness due to higher percentage of austenite reversion. No significant difference between the hardness values of AB + A and SOL + A specimens is observed. It can therefore be concluded that, in principle, conventional solution annealing and ageing can be dispensed with in favor of direct aging. However, as the results are based on small sized specimens, further investigations into the scalability are needed.

Dual‐Stoichiometry Copper Sulphide Nanoparticles by Laser Ablation in DMSO: Synthesis and Biomedical Applications for Enhanced Photothermal Therapy and Photoacoustic Imaging

AbstractCopper sulphide nanoparticles are synthesized by laser ablation of a copper target in DMSO by a 527 nm nanosecond pulsed laser. These nanoparticles have double stoichiometry (CuS and Cu1.8S) and crystalline structures, sizes under 30 nm, and they present substantial absorbance in the second near‐infrared window and photoluminescence in the visible region. The nanoparticles are used as photothermal and photoacoustic agents at 1080 nm and 1064 nm, respectively. Utilizing as a photothermal agent, these nanoparticles rapidly exhibit local heating, photothermal stability, and a temperature change of 52.2 °C within 300 s at 1 mg mL−1 concentration and 3.23 W cm−2 laser intensity. On the other hand, while employed as a photoacoustic agent, they enhanced the contrast significantly and increased the brightness proportional to their concentrations when compared to ultrasound imaging. Additionally, the biocompatibility properties of these nanoparticles were tested with cancer cells, and they were subjected to laser ablation to assess their photothermal effects. In this article, we demonstrate that copper sulphide nanoparticles synthesized by pulsed laser ablation hold great promise for photothermal and photoacoustic applications, especially in biomedical applications.

The optical properties of ZnO/ZnS:Mn core–shell nanorods prepared on GaN substrates

ZnO/ZnS:Mn/GaN core–shell nanorods device was obtained by depositing ZnO/ZnS:Mn core–shell nanorods on GaN substrate using pulsed laser deposition and hydrothermal method. The optical properties of the device were studied. The PL spectrum of ZnO/ZnS:Mn/GaN consists of four emission bands located at 375, 450, 530 and 590 nm. The forward opening voltage is about 6 V. Under forward bias, there are two luminescence bands located at 415 and 610 nm, and the intensity increases with the increase of forward voltage. The color coordinates of EL spectra are very close to standard white light, indicating that the device has potential application in white light LED. Compared to ZnO/GaN nanorods device, the white light quality of ZnO/ZnS:Mn/GaN core–shell nanorods device is better, and it is more suitable as a long-term light source.