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An improvement on the conversion efficiency of Si/CZTS solar cells by LSPR effect of embedded plasmonic Au nanoparticles
摘要： In this work, Au/Si/CZTS/Ag and Au/Si/plasmonic-CZTS/Ag solar cells have been produced using PLD technique. These CZTS solar cells have been produced based on p-type CZTS ultrathin films at different thicknesses of 61 nm, 112 nm and 210 nm which were grown on an n-type Si wafer. Morphologic and crystalline structures as well as optical characteristics of CZTS ultrathin films have been investigated by courtesy of AFM, XRD and UV–vis spectra. J-V characteristics of CZTS solar cells have been obtained under AM 1.5 solar radiation of 80 mW/cm2. It has been observed that Jsc, Voc and η values of CZTS solar cells increase as thickness of CZTS ultrathin films are diagnosed to an optimum thickness. But, CZTS ultrathin films at thickness of 61 nm and 112 nm have low absorption rate and it was observed that absorption rate of CZTS ultrathin films increase dramatically in visible and NIR regions after Au plasmonic nanoparticles were embedded in these CZTS ultrathin films. Furthermore, Jsc and η values of plasmonic CZTS solar cells increase and that increase can be attributed to the transfer of electrons from the plasmonic Au NPs to the conduction band of CZTS semiconductor, the photon absorption of CZTS ultrathin films from visible to NIR region in the wide spectral region, and the increase in the path length of light through in CZTS semiconductor by photon scattering of Au nanoparticles.
关键词： Ultrathin film,CZTS,Au,LSPR,PLD,Efficiency
更新于2025-09-19 17:13:59
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Visible-enhanced silver-doped PbI2 nanostructure/Si heterojunction photodetector: effect of doping concentration on photodetector parameters
摘要： This paper presents the effect of doping concentration on the properties of PbI2 nanostructure film and p-PbI2:Ag/n-Si photodetector prepared by pulsed laser deposition PLD method. The PbI2 film was doped with silver at doping concentrations of 1%, 3% and 5%. XRD results show that all deposited PbI2 films are polycrystalline and well-crystallized along (001) plane with hexagonal structure. The structural studies revealed that the grain size of the film decreases as the doping concentration increase. Energy dispersive X-ray EDX, scanning electron microscope SEM and elemental mapping analysis confirm the presence of Pb, I and Ag elements and the films were near stoichiometric. Raman spectra of PbI2 film showed the presence of Raman peaks located at 73, 94.3, 108, 165.7, and 208.9 cm?1 corresponding to E2 vibration modes, respectively, and a Raman peak at 185 cm?1 was observed for the film doped with 5 wt% which indexed to 2E1. The optical energy gap of the film decreased from 2.8 to 2.3 eV after doping with silver. Hall measurement confirms that the deposited PbI2 films are p-type and the electrical resistivity of the film increases from 1.1 × 104 to 1.8 × 107 ? cm as doping concentration increases from 1 to 5%.
关键词： PLD,Raman spectra,2H-polytype,PbI2,Photodetector,Ag:PbI2
更新于2025-09-19 17:13:59
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Study of TiO2 nanotubes decorated with PbS nanoparticles elaborated by pulsed laser deposition: microstructural, optoelectronic and photoelectrochemical properties
摘要： Titanium dioxide nanotube arrays (TiO2 NTAs) have been synthesized using the electrochemical anodization procedure. Lead sulfide nanoparticles (PbS NPs) were deposited on TiO2 NTAs (PbS NPs/TiO2 NTAs) using the pulsed laser deposition (PLD) method. The prepared samples (PbS NPs/TiO2 NTAs) were characterized using scanning electron microscopy, transmission electron microscopy (TEM), X-ray diffraction (XRD), UV–Vis spectroscopy and photoluminescence. The size of the PbS NPs was controlled by varying the number of laser pulses (NLP) during the PLD process. TEM observations show that the PbS NPs are in the range of 10–20 nm, consistent with the results obtained from XRD. HRTEM and diffuse reflectivity show that, at NLP ≥ 2500, the growth of the PbS NPs occurs on a previously formed PbS layer. Transmission and absorption spectra show that the PbS-NPs have an indirect optical bandgap which is particle size independent. This optical bandgap corresponds to excitonic transitions, which are greatly affected by oxygen defects, off-stoichiometry and other surface state defects, particularly for smaller NPs (NLP < 2500). The absorption spectra of the TiO2 NTAs show that the PbS NPs extend the absorption range of the TiO2-NTAs from the ultraviolet to the visible region, indicating that the PbS NPs/TiO2 NTAs heterojunction facilitates the separation of the photogenerated charge carriers. Photoelectrochemical analyses show that a maximum photocurrent current density of ~1.05 mA/cm2 and a photoelectrochemical conversion efficiency of 2.5% are reached for NLP = 2500 under an illumination of 100 mW/cm2 in the UV–Vis range.
关键词： TiO2 nanotubes,Photoelectrochemical properties,PbS nanoparticles,PLD
更新于2025-09-16 10:30:52
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AIP Conference Proceedings [AIP Publishing LLC OPTOELECTRONIC MATERIALS AND THIN FILMS: OMTAT 2013 - Kochi, Kerala, India (3–5 January 2013)] - Annealing effects on the structural and electrical properties of pulsed laser deposited BaPbO3 thin films
摘要： Conductive pervoskite BaPbO3 (BPO) ?lms as potential electrodes for ferroelectric / tuneable applications were prepared by pulsed laser deposition technique at 6000C and at 0.1 mbar oxygen partial pressure on fused silica substrates. The structural and electrical properties of the ?lms showed a dependence on annealing temperatures and the high oxygen ambient. XRD and standard four probe method with Hall setup were employed to investigate the dependence of growth conditions on crystal structure, resistivity and the carrier concentration on annealing the BPO thin ?lms. The surface topography was analysed by AFM. The unannealed as deposited ?lms showed the least resistivity of 1.6 x 10?2 ohm cm and a bandgap of 4.1eV.
关键词： BPO,PLD,Hall measurements
更新于2025-09-16 10:30:52
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In situ laser reflectivity to monitor and control the nucleation and growth of atomically-thin 2D materials
摘要： The growth of atomically-thin two-dimensional (2D) layered and other quantum materials is typically performed without in situ monitoring or control. Here, a simple laser reflectivity approach is demonstrated to provide in situ control over sub-monolayer thickness and growth kinetics during pulsed laser deposition (PLD) of MoSe2 layers. First, the general technique is presented with emphasis on designing the maximum sensitivity of the optical contrast through consideration of Fresnel’s equations with proper choice of layer thickness, substrate, and laser monitoring wavelength, incidence angle, and laser polarization. Then the 633 nm optical reflectivity of MoSe2 layers on SiO2/Si substrates was predicted and compared with in situ monitoring of MoSe2 growth by PLD under actual growth conditions using a probe HeNe laser beam. The measurements showed high sensitivity and excellent agreement with MoSe2 surface coverages calculated from atomic resolution STEM analysis of 2D layers deposited in arrested growth experiments. Growth kinetics revealed by these measurements showed sigmoidal nucleation and growth stages in the formation of the 2D MoSe2 layers that are described by a simple model, indicating the promise of the laser reflectivity technique for in situ monitoring and control of 2D materials deposition.
关键词： pulsed laser deposition (PLD),MoSe2,kinetic modeling,in situ reflectivity,2D materials
更新于2025-09-16 10:30:52
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An Experimental and Theoretical Comparison of Plasmonic Properties of Metallic Nano-Particles Have Different Morphological Properties
摘要： In this study, we have grown some plasmonic metal-nanoparticles have different morphological properties on the microscope slide and silicon wafer as substrates depending on an ambient background gas pressure and number of laser pulses by using Pulse Laser Deposition (PLD) technique in connection with a nanosecond Nd:YAG laser system. The morphology of these nanoparticles thin film was investigated by Atomic Force Microscopy. UV-vis spectra have shown that plasmonic metal- nanoparticles present a Localised Surface Plasmon Resonance band in visible and near-infrared (NIR) regions depending on the morphologic structure of the nanoparticles thin film. The LSPR of the plasmonic metal nanoparticles was calculated theoretically using Boundary Element Method simulation programme. The reliability of experimental results was verified by comparing the theoretical results with their experimental counterparts produced by using PLD, both were obtained in this work. Both theoretical and experimental results and their comparison have been presented and discussed in this study, and a conclusion has been made that the theoretical and experimental results for Cu were in all good agreement.
关键词： LSPR,BEM,nanoparticle,gas pressure,PLD
更新于2025-09-12 10:27:22
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Investigation of Conversion Efficiency of n-ZnO/p-Si Heterojunction Device Produced by Pulsed Laser Deposition (PLD)
摘要： In this study, n-ZnO/p-Si heterojunction was produced by growing polycrystalline Zinc Oxide (ZnO) thin films on p-type Si (100) substrate at 500 μm thickness using Pulsed Laser Deposition (PLD) method. The crystalline and morphologic structure of ZnO thin film were analysed by X-ray diffraction (XRD) and Atomic Force Microscopy (AFM) techniques. The photovoltaic (PV) property of n-ZnO/p-Si heterojunction was investigated by using current-voltage (J-V) measurement under illumination at 70 mW/cm2. The silver (Ag) metal thin film was deposited by PLD to make ohmic contacts to the n-ZnO/p-Si heterojunction structure. The barrier height and the ideality factor were calculated to be 0.51 eV and 12.37, respectively, at room temperature (RT). The largest values of open circuit voltage (Voc) and short circuit current density (Jsc) were about 250 mV and 1.63 mA/cm2, respectively. The photoelectric conversion efficiency in the range of 0.12% have been achieved and presented in this paper.
关键词： ZnO,efficiency,heterojunction,Si,PLD
更新于2025-09-12 10:27:22
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CdTe:Sn thin films deposited by the simultaneous laser ablation of CdTe and Sn targets
摘要： CdTe:Sn thin films were grown by pulsed laser deposition on glass substrates at room temperature. The study of the changes in the chemical, structural and optical properties of the films as a function of the density of Sn ions calculated from Langmuir planar probe measurements is presented. Four films were grown by the simultaneous ablation of CdTe and Sn targets in vacuum. The Sn ion density was modified by varying the fluence on the Sn target, while the CdTe plasma density was kept constant for all the deposits. The chemical composition was analyzed by XPS, where a dependence of the Sn incorporation into the CdTe lattice, on the Sn ion plasma density was demonstrated. The crystalline structure analysis by XRD showed a hexagonal structure for all the films. When the CdTe and Sn plasmas were combined, a preferential orientation in the plane (110) was observed for the resulting films. Furthermore, as Sn plasma density increased, the intensity of the (110) peak increased as well, suggesting that crystalline re-orientation is an effect of Sn incorporated into the CdTe lattice. Vibrational behavior was analyzed by Raman spectroscopy. A vibrational mode appeared at 118 cm-1 and was related to a Sn-Te vibration, suggesting the incorporation of substitutional Sn into the CdTe lattice. The Sn-Te bonding was confirmed by XPS by the appearance of signals centered at 485 and 494 eV, which correspond to Sn2+ in SnTe. Thin films thicknesses values were between 320 and 460 nm increasing with Sn ion density. The band gap calculated using UV-Vis spectrophotometry, resulted in values ranging from 1.42 to 1.46 eV. PL measurements showed a slight blue shift of the near-edge emission as Sn plasma density increased.
关键词： PLD,CdTe:Sn,plasmas
更新于2025-09-12 10:27:22
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Influence of the buffer layers on growth and quality of graphene films grown by pulsed laser deposition
摘要： Graphene films were grown onto two different thickness levels of SiO2/Si substrates, with the help of Ni film from highly ordered pyrolytic graphite through pulsed laser deposition. In this work, the influence of thickness of buffer layer of SiO2 on quality, growth, and crystallinity of graphene films in terms of substrate temperatures has been studied. All graphene samples were characterized by using Raman spectroscopy, Scanning electron microscopy (SEM), and X-ray photoelectron spectroscopy (XPS). The micro-Raman spectroscopic results clearly reveal that carbon bond strength increased while defects reduced on SiO2 (100 nm)/Si substrates with the increment in substrate temperature from 700 °C to 800 °C. Moreover, it was also observed from the Raman spectra that the number of graphene layers continuously improved over commercially available SiO2 substrates with the increase growth temperature from 700 °C to 800 °C. Thus, the presented study provides a facile, rapid, and effective technique to control the quality, growth, and crystallite size of graphene films onto different thickness SiO2 layer on Si.
关键词： Raman Spectroscopy,SEM,Graphene,PLD,XPS
更新于2025-09-12 10:27:22
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Pure carbon conductive transparent electrodes synthetized by a full laser deposition and annealing process
摘要： One of the biggest challenge that face optoelectronic and photovoltaic devices is the necessity to provide a reliable alternative to transparent conducting oxide (TCO) like Indium Thin Oxide (ITO). We recently published a study proposing a method to produce transparent conductive electrodes only based on carbon materials. In a first step, we use the Pulsed Laser Deposition (PLD) to produce high performance DLC. Those thin films own very interesting properties in kindship with diamond, like high transparency in the visible range, chemical inertness and biocompatibility. In addition, the DLC is a perfect electrical insulator and presents a relative high opacity in ultra-violet (UV). This particularity has a great interest to perform, in a second step, UV laser annealing over the DLC surface. The aim is to break the existing diamond bindings (sp3 hybridization) on the surface and allow atoms being reorganized in graphitic bindings (sp2 hybridization). We demonstrate that the increase of atomic graphitic bindings leads to a valuable surface conductivity. According to optimized annealing parameters, the surface conductivity reaches values comparable to ITO. We also show that the laser treatments only sparsely affects the DLC transparency. Moreover, this full laser-based process remains compatible with the standard microelectronic technological steps.
关键词： Diamond-Like Carbon (DLC),Graphitization,Pulsed Laser Deposition (PLD),Transparent electrodes,Laser surface annealing
更新于2025-09-12 10:27:22