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AIP Conference Proceedings [Author(s) PROCEEDINGS OF THE INTERNATIONAL CONFERENCE OF COMPUTATIONAL METHODS IN SCIENCES AND ENGINEERING 2017 (ICCMSE-2017) - Thessaloniki, Greece (21–25 April 2017)] - Synthesis of energy-efficient FSMs implemented in PLD circuits
摘要： The paper presents an outline of a simple synthesis method of energy-efficient FSMs. The idea consists in using local clock gating to selectively block the clock signal, if no transition of a state of a memory element is required. The research was dedicated to logic circuits using Programmable Logic Devices as the implementation platform, but the conclusions can be applied to any synchronous circuit. The experimental section reports a comparison of three methods of implementing sequential circuits in PLDs with respect to clock distribution: the classical fully synchronous structure, the structure exploiting the Enable Clock inputs of memory elements, and the structure using clock gating. The results show that the approach based on clock gating is the most efficient one, and it leads to significant reduction of dynamic power consumed by the FSM.
关键词： PLD,synchronous circuit,finite state machine,low power circuits,power dissipation
更新于2025-09-23 15:21:21
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Recent progress in high-performance photo-detectors enabled by the pulsed laser deposition technology
摘要： In the past decade, photo-detectors have been demonstrated to have very important applications in image sensing, optical communication, fire detection, environmental monitoring, space exploration, safety detection, and many other scientific research and industrial technology fields and are regarded as the key components of wearable devices. Compared to traditional fabrication approaches, pulsed-laser deposition (PLD)-grown materials for photo-detectors offer several merits. First, PLD is a clean physical vapor deposition approach. A stoichiometric amount of atoms can be transferred from the target to the substrate, avoiding complicated and potentially dangerous chemical reactions. Furthermore, the PLD process is carried out in a high-vacuum environment. Therefore, almost no contaminants, such as catalysts, precursors, surfactants and by-products, will be introduced. Also, the thickness of the films can be controlled by simply manipulating the energy and pulse number of the pulsed laser. Furthermore, the fabrication temperature is relatively low, which is available to deposit materials on various substrates, even flexible ones. Most importantly, PLD is a deposition technology with large area coverage, which can produce centimeter-scale thin films, the planar geometry of which has significant potential for compact device integration with modern semiconductor techniques. Consequently, this review introduces the recent advances on the materials, fabrication, and application of pulsed-laser deposition for a variety of high-performance photo-detectors from an overall perspective. Moreover, the challenges and future development trends are discussed.
关键词： wearable devices,fabrication,optoelectronics,applications,photo-detectors,PLD,pulsed-laser deposition,high-performance,materials
更新于2025-09-23 15:21:01
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Structural, Morphological, and Optical Properties of Iron Doped WO3 Thin Film Prepared by Pulsed Laser Deposition
摘要： The iron doped tungsten-oxide (Fe and WO3) thin ?lm with di?erent morphology and crystalline structures were obtained for di?erent substrate temperatures at the oxygen pressure of 14.66 Pa. The Fe-doped WO3 ?lms were deposited by pulsed laser deposition (PLD). The in?uence of the substrate temperature on the surface and on the crystalline phases of the ?lms was studied. The XRD (X-ray di?raction) analysis indicates the changing in the crystalline phases from γ-monoclinic to a mixture of γ-monoclinic and hexagonal phases dependent on the temperature of annealing and as-grown ?lms. Related to the as-grown and annealing ?lms conditions, the SEM (scanning electron microscopy) shows a change in the image surface from nanoneedles, to nanoporous, and further to long nanowires and broad nanobands. Energy-dispersive X-ray spectroscopy (EDX) shows the elemental composition of the Fe-doped WO3 ?lm as-grown and after annealing treatment. Raman spectroscopy presented the main vibration mode of the Fe-doped WO3 thin ?lm. The optical energy bandgap of the ?lms is decreasing as the substrate temperature increases.
关键词： PLD method,tungsten trioxide,Fe-doped WO3,structural and morphological characterization
更新于2025-09-23 15:21:01
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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
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Construction of Cr2O3:ZnO Nanostructured Thin Film Prepared by Pulsed Laser Deposition Technique for NO2 Gas Sensor
摘要： Rhombohedral structure of chromium oxide (Cr2O3) thin-film doped hexagonal zinc oxide (ZnO) nanoparticles have been prepared using pulsed laser deposition technique at a different weight percent of ZnO from 0 to 9 wt%. The results of X-ray diffraction analysis shown that the doped films are polycrystalline, and the average crystallite size of the synthesized thin films is found to be dependent on the ZnO concentration. The surface morphology of the prepared thin films was characterized by atomic force microscopy. The optical properties are investigated using ultraviolet–visible light (UV–Vis) absorption spectroscopy. The optical bandgap ranged from 2.45 to 2.68 eV, showing the shift towards longer-wavelength compared to bulk Cr2O3 (~ 3 eV). The sensitivity, response, and recovery times of the sensor towards nitrogen dioxide (NO2) gas were studied and discussed. The sensitivity increase with increasing the doping concentration, and started to decrease when ZnO concentrations reach 7 wt%. The optimal ZnO concentrations for NO2 gas sensitivity is 5 wt%, which attain maximum sensitivity of 87.5% at temperature of 523 K.
关键词： Cr2O3:ZnO nanostructure,Structural properties,Optical properties,Gas sensitivity,PLD technique
更新于2025-09-23 15:19:57
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Development of Pd/TiO2 Porous Layers by Pulsed Laser Deposition for Surface Acoustic Wave H2 Gas Sensor
摘要： The influence of sensitive porous films obtained by pulsed laser deposition (PLD) on the response of surface acoustic wave (SAW) sensors on hydrogen at room temperature (RT) was studied. Monolayer films of TiO2 and bilayer films of Pd/TiO2 were deposited on the quartz substrates of SAW sensors. By varying the oxygen and argon pressure in the PLD deposition chamber, different morphologies of the sensitive films were obtained, which were analyzed based on scanning electron microscopy (SEM) images. SAW sensors were realized with different porosity degrees, and these were tested at different hydrogen concentrations. It has been confirmed that the high porosity of the film and the bilayer structure leads to a higher frequency shift and allow the possibility to make tests at lower concentrations. Thus, the best sensor, Pd-1500/TiO2-600, with the deposition pressure of 600 mTorr for TiO2 and 1500 mTorr for Pd, had a frequency shift of 1.8 kHz at 2% hydrogen concentration, a sensitivity of 0.10 Hz/ppm and a limit of detection (LOD) of 1210 ppm. SAW sensors based on such porous films allow the detection of hydrogen but also of other gases at RT, and by PLD method such sensitive porous and nanostructured films can be easily developed.
关键词： bilayer films,pulsed laser deposition (PLD),palladium,hydrogen sensor,surface acoustic wave (SAW),Pd/TiO2,porous morphology,titanium dioxide
更新于2025-09-23 15:19:57
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Preparation and deposition of Pr-Fe-B permanent magnet powder using pulsed laser
摘要： We have already prepared a thin permanent magnet with the thickness of sub millimeter by obtaining magnet powders using a PLD (Pulsed Laser Deposition) method. In the study, the PLD followed by a flash annealing enabled us to deposit isotropic Pr-Fe-B magnet powders with coercivity (Hcj) > 1000 kA/m on a stainless thin shaft applicable to a miniaturized motor. Observation on the surface of Pr-Fe-B magnets and evaluation on mechanical behavior was carried out. Since the surface of a Pr-Fe-B magnet was coated by a Pr oxide through an annealing process, their magnetic properties didn’t degrade after one year. We also confirmed that the Pr-Fe-B magnet has possibility to be applied to a micro magnetization process. It was clarified that the powder technology using the PLD is useful to propose a thin magnet applicable to a next generation small motor.
关键词： stainless shaft,coating,Pr-Fe-B permanent magnet powder,PLD (Pulsed Laser Deposition)
更新于2025-09-19 17:13:59
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Effect of background atmosphere and substrate temperature on SrO:Bi3+(0.2 mol%) thin films produced using pulsed laser deposition with different lasers
摘要： SrO:Bi3+ (0.2 mol%) phosphor thin films were grown by pulsed laser deposition (PLD) on Si (100) substrates in vacuum and different O2 atmospheres at different substrate temperatures using a Nd:YAG laser (266 nm) with energy 33.3 mJ/pulse, a KrF laser (248 nm) with energy 300 mJ/pulse or a ArF laser (193 nm) with energy 150 mJ/pulse. The microstructure and photoluminescence (PL) of these films were found to be highly dependent on the background atmosphere and substrate temperature. X-ray diffraction (XRD) analysis showed that the SrO:Bi3+ (0.2 mol%) films varied from amorphous to highly crystalline depending on the deposition conditions. Atomic Force Microscope results showed that the surface roughness decreased as the substrate temperature increased. The main PL emission peak position of the thin films showed a shift to shorter wavelengths at 427 nm, when compared to the powder (445 nm). The difference in wavelength was attributed to the Bi3+ ions, which are very sensitive towards the environment. Time of flight secondary ion mass spectroscopy depth profiles for the samples deposited in vacuum and O2 at different substrate temperatures look similar, except for a slight thickness variation.
关键词： Different lasers,Substrate temperature,PLD,Oxygen pressures
更新于2025-09-19 17:13:59
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Pulsed laser deposition of a ZnO:Eu3+ thin film: study of the luminescence and surface state under electron beam irradiation
摘要： A highly c-axis orientated Eu3+ doped ZnO (ZnO:Eu3+) thin film was successfully deposited by pulsed laser deposition in an oxygen working atmosphere. The structure, morphology, chemical analysis and luminescence properties of the sample were investigated. The effect of electron beam irradiation on the surface state, chemical and luminescence properties of the sample were studied. Successful incorporation of Eu3+ ions in the ZnO matrix was confirmed by X-ray diffraction (XRD) and x-ray photoelectron spectroscopy (XPS) analysis. XPS measurements revealed traces of the divalent (Eu2+) on the film surface while the trivalent (Eu3+) oxidation state in the bulk of the film. XPS depth profile confirmed that the film contained excess oxygen throughout the film. The film exhibited exciton and defect emission of ZnO as well as 4f – 4f characteristic emission of Eu3+ ions superimposed on the defect emission when excited at 325 nm using a He-Cd laser. Whereas only 4f – 4f characteristic emission of Eu3+ ions was recorded when the film was excited at 464 nm and also when excited with the electron beam. XPS high resolution spectra of the O 1s peak confirmed the creation of new defects during electron beam irradiation. In general, ZnO:Eu3+ films show potential for applications as a source of red light in optoelectronic devices.
关键词： Degradation,PLD,ZnO thin film,Eu3+ ions,Cathodoluminescence,Red emission,Electron beam irradiation
更新于2025-09-19 17:13:59
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[IEEE 2019 Conference on Lasers and Electro-Optics Europe & European Quantum Electronics Conference (CLEO/Europe-EQEC) - Munich, Germany (2019.6.23-2019.6.27)] 2019 Conference on Lasers and Electro-Optics Europe & European Quantum Electronics Conference (CLEO/Europe-EQEC) - Spectroscopic and Structural Properties of Yb <sup>3+</sup> -Doped and Undoped 2D-Mos <sub/>2</sub> Thin Films for Optoelectronic and Photonic Device Applications
摘要： Molybdenum disulphide (MoS2) has layered structure and is classed as a transition metal-disulphide (TMD) material. Recently it has drawn significant attention for exploring optoelectronic and photonic properties on sub-nanometre scale, with a potential for accessing quantum interactions [1]. The electronic structure and stoichiometry of TMDs make them distinguishable from the metallic graphene, as the TMDs depict a clear bandgap, as in compound semiconductors [2], which is quite attractive for device engineering and applications in photovoltaic, energy storage, and bandgap engineered light-sources [3]. In this research, the fabrication of undoped and Yb3+-ion doped MoS2 nanometre (nm)-scale thin films are discussed using femto-second pulsed laser deposition (fs-PLD) and the structural and spectroscopic properties of fs-PLD are compared with liquid-phase epitaxy grown undoped MoS2 films. Such a comparative analysis may offer materials fabrication platform in future for engineering optoelectronic and photonic devices on silica glass and silicon platforms.
关键词： DFT,Raman spectroscopy,nonlinear optical properties,Molybdenum disulphide,fs-PLD,photonic devices,Yb3+-doped,optoelectronic,thin films
更新于2025-09-19 17:13:59