- 标题
- 摘要
- 关键词
- 实验方案
- 产品
-
Selective area laser-assisted doping of SiC thin films and blue light electroluminescence
摘要： Laser-assisted doping combined with annealing technique is used in selective areas to form a p–n junction on a SiC thin film grown by the pulsed laser deposition on a Si substrate at a temperature of 800 °C. This approach in an aluminum chloride solution and a phosphoric solution has resulted in p-SiC/n-Si and n-SiC/p-Si hetero-structures, respectively. Further, a functional in-plane p–n junction is realized side-by-side on the post-deposited SiC thin film. I–V characteristics by two probe technique showed the p–n diode characteristics. Blue light (400 nm) electroluminescence from the p–n junction on SiC thin film was observed in the forward biased condition. Further, an improvement in the I–V reverse characteristics was observed by illuminating the p–n SiC thin film with green/blue light.
关键词： pulsed laser deposition,laser assisted doping,SiC thin film,electroluminescence,silicon carbide,selective area doping
更新于2025-09-23 15:19:57
-
Selective laser ablation and patterning on Ag thin films with width and depth control
摘要： Silver (Ag) films were deposited on glass substrates by radio frequency (RF) magnetron sputtering and then ablated by a 532 nm nanosecond pulsed laser. The effects of laser fluence and defocusing amount on the width and depth of laser-ablated grooves on 100- and 600-nm-thick Ag films were systematically investigated under single- and multi-scan ablation. The results suggested that the Ag films could be successfully removed from the substrate owing to laser-induced thermoelastic force or vaporization. It was confirmed that laser fluence and defocusing amount played very important roles in controlling the width and depth of the laser-ablated grooves. In the present work, grooves with widths ranging from 53 to 196 μm and depths ranging from 56 to 196 nm were obtained on 100-nm-thick Ag films by single-scan laser ablation, and laser ablation or removal with controllable depths was realized on 600-nm-thick Ag films by adopting single- or multi-scan (i.e., scanning numbers of 1–6). Furthermore, square spiral Ag patterns were successfully obtained by single- and multi-scan laser ablation and showed good electrical conductivity in a simple circuit. This work may have great potential applications in various fields that demand width and depth control of laser ablation/removal.
关键词： Width and depth control,Laser ablation,Ag thin films,RF magnetron sputtering,Nanosecond pulsed laser
更新于2025-09-23 15:19:57
-
Discovery of Several New Families of Saturable Absorbers for Ultrashort Pulsed Laser Systems
摘要： Saturable Absorber (SA) is a key element of any passive mode-locked laser system to provide ultrashort laser system. So far various materials have been proposed that could be used for this purpose. However, the field is still looking for new ways to make the fabrication process easier and cost-effective. Another challenge in testing mode-locked laser systems using various SA samples is the lack of knowledge in preparing these by laser physicists given this is outside their remit of expertise. In this study, we have proposed a novel method to produce these SAs from plastic materials and glycol. Our new method relies upon increase in thickness up to a value where the modulation depth is enough to give stable ultrashort pulses. Although we have shown this method for four materials; similar approach could be applied to any material. this will open the door of unlimited families of SAs that could be easily prepared and applied without any prior knowledge in material sciences.
关键词： Mode-locked laser,Glycol,Plastic materials,Saturable Absorber,Ultrashort pulsed Laser Systems
更新于2025-09-23 15:19:57
-
Metal organic frameworks composite Eu2O3@[Zn2(1,4-ndc)2dabco] synthesized by pulsed laser ablation in flowing liquid and its fluorescent sensing of fatty alcohol with different branch chains
摘要： This work reports the metal organic frameworks composite Eu2O3@[Zn2(1,4-ndc)2dabco] synthesized by pulsed laser ablation in flowing liquid. Powder X-ray Diffraction (PXRD) and SEM were used to characterize its structure and morphology. The results show that the Eu2O3 nanoparticles with the average particle size of 3.08 nm are uniformly distributed among the crystal and the BET specific surface area of the composite Eu2O3@[Zn2(1,4-ndc)2dabco] is 1087 m2/g. At 296 K, the adsorption capacities of C2H2 on composite are up to 117.3 cm3/g, which is larger than that of the compound [Zn2(1,4-ndc)2dabco]. The C2H6/CH4 selectivity of the composite Eu2O3@[Zn2(1,4-ndc)2dabco] is 25.9 and much higher than that of some familiar MOFs materials. Moreover, the composite Eu2O3@[Zn2(1,4-ndc)2dabco] can emit very intense characteristic fluorescence at 613 nm of Eu3t ion under ultraviolet radiation and can be used for detecting of fatty alcohols with different branch chains in fluorescence sensing because of its fluorescence intensity at 613 nm is sensitive to fatty alcohol with different carbon chains. The luminescence based sensing mechanism of the composite Eu2O3@[Zn2(1,4-ndc)2dabco] was discussed.
关键词： Flowing liquid,MOFs composites,Adsorption,Fatty alcohol with different branch chains,Pulsed laser ablation,Fluorescent sensing
更新于2025-09-23 15:19:57
-
Effect of numerical aperture on molten area characteristics in micro-joining of glass by picosecond pulsed laser
摘要： Glass products with precise and sophisticated shapes are highly demanded in the field of MEMS due to their excellent properties. Ultrashort pulsed laser has been expected to be a powerful and reliable tool for micro-welding of glass. Focusing condition such as numerical aperture (N.A.) is a critical parameter that controls how ultrashort laser pulses interact with and propagate in glass, and it has a great influence on the laser micro-welding characteristics of glass. In order to investigate the quality of welding process, it is important to understand the dependence of the mechanical strength of molten area created in glass specimen with various numerical apertures. Therefore, the mechanical strength of molten area with various numerical apertures was evaluated in micro-welding of glass by picosecond pulsed laser. Higher bending strength could be obtained under an appropriate volume ratio of molten area and glass specimen, when continuous molten areas were formed. In addition, high density and large size of molten area without crack led to higher breaking stress. It is concluded that superior focusing characteristics such as N.A. 0.65 enable a long region of high power density in beam axis, which can satisfy both high mechanical strength and high processing speed.
关键词： Picosecond pulsed laser,Breaking stress,Bending strength,Glass material,Numerical aperture
更新于2025-09-23 15:19:57
-
Investigation of KBiFe <sub/>2</sub> O <sub/>5</sub> as a Photovoltaic Absorber
摘要： KBiFe2O5 (KBFO) was grown by pulsed laser deposition (PLD) on SrTiO3 (001) (STO), 1 at% Nb-SrTiO3 (001) (Nb-STO) and MgAl2O4 (001) (MAO). In the case of MAO substrate, epitaxial growth is obtained. As its bandgap is relatively low (1.6 eV in the bulk), KBFO is a promising candidate for oxide photovoltaics. In this work we examine the growth of KBFO by PLD by looking at its structure and composition and we investigate the optical properties of the films obtained. A photovoltaic architecture based on KBFO films is proposed and a solar cell behaviour based on KBFO absorber is obtained.
关键词： pulsed laser deposition,solar cell,thin film,photovoltaics,oxide
更新于2025-09-23 15:19:57
-
Laser-Generated BiVO4 Colloidal Particles with Tailoring Size and Native Oxygen Defect for Highly Efficient Gas Sensing
摘要： To alleviate the poor sensing performance of BiVO4, developing new strategies for the fabrication of unique device with improved sensing properties is very necessary and has great practical significance. In this work, size-tailored and uniform black BiVO4 colloids with abundant oxygen vacancy were synthesized by a unique method of pulsed laser irradiation of colloidal nanoparticles (PLICN). The corresponding laser irradiation effects on the sensing properties are comparatively investigated. The results indicate that the BiVO4 nanospheres with average size of 50 nm shows best sensing properties with high sensitivity, superior selectivity, low detection limit (44 ppb) to H2S at low working temperature (75 oC). Its sensing response is over 4 times higher when comparing with that of the raw material. Further investigation manifests that laser irradiation could induce quantity of the oxygen vacancy and decrease the resistance of the sensing device, which is mainly responsible for the enhanced sensing performance. Moreover, the density functional theories (DFT) calculations suggest that the oxygen vacancies can greatly decrease the surface absorption energy with enhanced H2S absorption capability on BiVO4 surface and lower the bader charger transfer from the absorbed H2S molecules to the BiVO4, thus enabling the implementation for the enhanced gas-sensing properties.
关键词： Pulsed laser irradiation,Hydrogen sulfide,Bismuth vanadate,Nanosphere,Gas sensor
更新于2025-09-23 15:19:57
-
High performance UV photodetector based on MoS2 layers grown by pulsed laser deposition technique
摘要： Highly efficient ultraviolet (UV) photodetector based on MoS2 layers has been fabricated using pulsed laser deposition (PLD) technique. Systematic layer dependent photoresponse studies have been performed from single layer to 10 layers of MoS2 by varying the laser pulses to see the effect of the number of layers on the photoelectrical measurements. Raman and Photoluminescence studies have been carried out to ensure the growth of high-quality MoS2 layers. Layers of MoS2 grown at 100 pulses were found to exhibit the characteristic Raman phonon modes i.e. E1 2g and A1g at 383.8 cm-1 and 405.1 cm-1 respectively and Photoluminescence (PL) spectra show B exciton peak for MoS2 at around 625 nm suggesting the growth of high-quality MoS2 layers. Atomic force microscopy (AFM) thickness profiling and cross sectional-high resolution transmission electron microscopy (HRTEM) analysis gives the thickness of grown MoS2 to be 2.074 nm and 1.94 nm, respectively, confirming the growth of trilayers of MoS2. X-ray photoelectron spectroscopy (XPS) spectra of the grown trilayer sample show characteristic peaks corresponding to Molybdenum and Sulphur doublet (Mo4+ 3d5/2,3/2 and S 2p3/2,1/2) confirming the chemical state of pure MoS2 phase without the presence of any Molybdenum oxide state. Dynamic photoelectrical studies with Indium Tin Oxide (ITO) as contact electrode upon UV laser illumination show superior responsivity of 3×104 A/W at 24 μW optical power of the incident laser (λ=365 nm) and very high detectivity of 1.81×1014 Jones at a low applied bias of 2 V. The obtained results are highly encouraging for the realization of low power consumption and highly efficient UV photodetectors based on MoS2 layers.
关键词： Pulsed laser deposition technique (PLD),2D material,UV photodetector,ITO electrode,cross-sectional TEM,Raman,MoS2 layers,XPS,AFM
更新于2025-09-23 15:19:57
-
Tetragonal tungsten bronze phase thin films in the Ka??Naa??Nba??O system: Pulsed laser deposition, structural and dielectric characterizations
摘要： Pulsed laser deposition parameters have been determined to synthesize pure Tetragonal Tungsten Bronze (TTB) phase thin films in the (K,Na)-Nb-O system (KNN). In relation to the high volatility of alkaline elements, it was found that the target composition and the target-substrate distance are of first importance. The TTB phase was identified by X-ray and electron diffraction and the surface microstructure consisting mainly of nanorods supports the formation of hallmark of the TTB phase. Poly-oriented nanorods have been obtained on both C-plane sapphire and (111)Pt/TiO2/SiO2/(001)Si substrates whereas horizontal nanorods oriented along the (hk0) planes have been grown on (100) and (110) SrTiO3. All the nanorods are parallel together when grown on (110) SrTiO3 and they present two in-plane orientations rotated of 90° from each other on (100) SrTiO3. Dielectric characteristics (dielectric permittivity e r, and loss tangent tand ) have been measured at low (1 kHz - 1 MHz) and high (1 GHz - 40 GHz) frequencies, on films deposited on Pt coated silicon and sapphire, respectively. A value of e r = 200 at 1 kHz with tand = 0.015 were measured in a parallel plate capacitor configuration, whereas e r = 130 and tand = 0.20 at 10 GHz were retrieved from transmission lines printed on the KNN TTB thin film grown on C-plane sapphire. Raman investigations of the TTB films were performed in the temperature range 77 - 873 K, confirming the TTB phase formation and the absence of structural transition. Piezoelectric Force Microscopy measurements evidenced a piezoelectric signal although no switching could be performed. However the dielectric measurements, complicated by high leakage currents when a DC voltage was applied, did not evidence any proof of ferroelectricity for the undoped KNN TTB films whereas results reported on other niobates (A,A')0.6Nb10O30 (with A: K, Na and A': Sr, Ba, Ca) have shown Curie temperatures, lying between 156°C and 560°C, separating the paraelectric phase (space group: P4/mbm N°127) and the ferroelectric one (space group: P4bm N°100).
关键词： Tetragonal Tungsten Bronze,Nanorods,Dielectric characterizations,K-Na-Nb-O system,Pulsed laser deposition
更新于2025-09-23 15:19:57
-
nano structured films induced by laser plasma ionization deposition
摘要： This research explores the optical properties of a large group of silicon/silica nanofibrous thin films. A picosecond pulse laser was employed for indirect deposition of ablated silicon on glass substrates. Prominent parameters such as laser power, repetition rate, pulse duration and scanning speed were changed to vary the structural and compositional properties of synthesized nanofibrous thin films. Transmission and specular reflection measurements along with material characterization techniques, Raman and FTIR, were employed for better interpretation of the results. By and large, an increase in the values for repetition rate and scanning speed produced a corresponding increase in optical data intensity, while an increase in power and pulse duration produced a drop in the same data. The results show that degree of oxidation and inherent porous structure are driving the light interaction in thin samples, as indicated by the changes in intensity or spectrum shape. Observation of these trends enabled us to apply tunable fabrication procedures to obtain desired groups of nanofibrous thin films. Electron and optical microscopy as well as background knowledge certify tangled nano-wired morphology in most cases. Structures with highly desirable usages, such as in sensing technology, can be optimized by their porosity, density and thickness.
关键词： Optical spectroscopy,Thin film,Pulse duration,Pulsed laser,Nano-fibers
更新于2025-09-23 15:19:57