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Production and photovoltaic characterisation of n-Si/p-CZTS heterojunction solar cells based on a CZTS ultrathin active layers
摘要： In this study, Au/n-Si/p-CZTS/Ag solar cells have been produced by using PLD technique. Ultrathin CZTS films have been grown on n-Si wafer in different thicknesses depending on number of laser pulses. These ultrathin CZTS films were analysed by XRD, AFM and UV-vis spectra. J-V characteristics of Au/n-Si/p-CZTS/Ag solar cells have been determined based on thickness of ultrathin CZTS films under AM 1.5 solar radiation of 80 mW/cm2. Short circuit current density (mA/cm2), fill factor, open circuit voltage (V) and power conversion efficiency (%) of ultrathin CZTS film solar cells have been determined for device produced in this work. The photovoltaic (PV) characteristics of ultrathin CZTS film solar cells has been discussed in detail in this present article and, as a result, the ideal ultrathin CZTS film solar cell structure having the highest efficiency has been determined and concluded.
关键词： efficiency,ultrathin films,Solar cell,PLD,CZTS,Si
更新于2025-09-11 14:15:04
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Preparation of visible-enhanced PbI2/MgO/ Si heterojunction photodetector
摘要： Fabrication and characterization of p-PbI2/MgO/n-Si photodetectors by pulsed laser deposition within (2.7-2.5) eV. The current-voltage and capacitance-voltage properties of PbI2/MgO/Si photodetector were investigated. The best responsivity of p-PbI2/MgO/n-Si photodetectors was ~ investigated using x-ray diffraction XRD, UV-Vis absorption and scanning electron microscope SEM. The XRD results revealed a single crystalline MgO with cubic structure along the (200) PLD under different deposition temperatures Ts were demonstrated for the first time. Structural, optical and morphological properties of nanostructured MgO and PbI2/MgO films were plane, while the PbI2 film deposited on MgO was a single crystalline with hexagonal phase along (001) plane. The optical energy gaps of PbI2 films deposited on MgO film were found to be perovskite solar cells, photodetectors, X-ray detectors, photoconductors, biological labeling and diagnostics, active matrix flat panel imagers, and γ-ray detectors [3, 4]. PbI2 films are usually prepared thermal evaporation, chemical methods, pulsed laser deposition, atomic layer deposition, and electron beam evaporation [5-8]. The wider optical energy gap MgO (7.3 eV at room temperature) is a non-toxic, high specific surface reactivity and cubic crystal structure with Fm-3m space group and transparent at the visible light. MgO films have been used in many [1, 2]. Lead iodide has been used in numerous applications, for example, light emitting diodes, Lead iodide has a hexagonal structure with optical band gap around 2.2eV at room temperature Keywords: PbI2; MgO; PLD; Heterojunction; Silicon; photodetector; Deposition temperature 0.88A/W at 410nm when the photodetector was prepared at Ts = 45°C.
关键词： Silicon,photodetector,MgO,Deposition temperature,PbI2,Heterojunction,PLD
更新于2025-09-11 14:15:04
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Optical Properties of Co-doped ZnSe Thin Films Synthesized by Pulsed Laser Deposition
摘要： Effects of Co concentration on the properties of ZnSe:Co films were investigated. The amorphous and crystalline (ZnSe)1-x:Cox (x=0.1, 0.3, 0.5) thin films were grown on sapphire (Al2O3) substrates with temperature of 25°C and 800°C respectively by pulsed laser deposition. The X-ray diffraction analyses indicate that, with increasing Co concentration, the average grain size decrease whereas the microstrain and dislocation density increase. Meanwhile, the further investigation for crystalline thin films shows that the crystalline phase transform from single cubic zinc blende structure to a mixture structure containing a small amount of hexagonal wurtzite phase. The Raman spectra and X-ray photoelectron spectroscopy reveal that the Co atoms were incorporated into ZnSe lattice and the samples reached an overdoping state when the x value surpassed 0.3. With increasing Co concentration, the average transmittance of films decreased due to the Co impurities un-incorporating into ZnSe lattice. Meanwhile, the band gap Eg values of films increased from 3.17 eV to 3.50 eV for TS=25°C and from 2.86 eV to 3.34 eV for TS=800°C. The large Eg values with regard to that of undoped bulk ZnSe (~2.7eV) can be attributed to the Co doping and quantum confinement effect. Moreover, the refractive index of the films increased by improving Co concentration. The dispersion energy Ed, oscillator energy Eo, static refractive index n0, static dielectric constant ε0, oscillator strength So and oscillator wavelength λo are analyzed by a single oscillator model. All these parameters were found to be dependent upon the Co concentration in the (ZnSe)1-x:Cox thin films.
关键词： Thin film,(ZnSe)1-x:Cox,Optical properties,Structure,PLD
更新于2025-09-11 14:15:04
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Epitaxial thin films as a model system for Li-ion conductivity in Li <sub/>4</sub> Ti <sub/>5</sub> O <sub/>12</sub>
摘要： Using an epitaxial thin-film model system deposited by pulsed laser deposition, we study Li-ion conductivity in Li4Ti5O12, a common anode material for Li-ion batteries. Epitaxy, phase purity, and film composition across the film thickness are verified employing out-of-plane and in-plane X-ray diffraction, transmission electron microscopy, time-of-flight mass spectrometry, and elastic recoil detection analysis, respectively. We find that epitaxial Li4Ti5O12 behaves like an ideal ionic conductor that is well described by a parallel RC equivalent circuit, with an ionic conductivity of 2.5·10-5 S/cm at 230 °C and an activation energy of 0.79 eV in the measured temperature range from 205 °C to 350 °C. Differently, in a co-deposited polycrystalline Li4Ti5O12 thin film with average in-plane grain size <10 nm, a more complex behavior with contributions from two distinct processes is observed. Ultimately, epitaxial Li4Ti5O12 thin films can be grown by pulsed laser deposition and reveal suitable transport properties for further implementation as zero-strain and grain boundary free anodes in future solid-state microbatteries design.
关键词： anode,polycrystalline,thin film,Li4Ti5O12,LTO,battery,epitaxial,PLD
更新于2025-09-10 09:29:36
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Nitric Oxide Detector Based on WO <sub/>3</sub> -1wt%In <sub/>2</sub> O <sub/>3</sub> -1wt%Nb <sub/>2</sub> O <sub/>5</sub> with State-of-the-Art Selectivity and ppb-Level Sensitivity
摘要： Fast, sensitive, and precise detection of nitric oxide (NO) is critical to many applications in environmental monitoring and early disease diagnosis via respiratory testing. An effective detection system requires a sensor to detect NO gas at the parts per billion (ppb) level, and this system should possess a high degree of anti-interference selectivity. To achieve these targets, a series of gas sensor thin films based on intrinsic WO3, one-additive-doped WO3 (prepared by doping In2O3 or Nb2O5), and two-additive-doped WO3 (synthesized by doping with In2O3 and Nb2O5) oxides were successfully grown. By analyzing the properties of sensitivity, selectivity, responsiveness, and recovery time of the gas sensors, we found that WO3-1wt%In2O3-1wt%Nb2O5 has overwhelming advantages over intrinsic WO3, WO3-In2O3, and WO3-Nb2O5. A sensing response value of 2.4 was observed for NO concentrations as low as 20 ppb from the WO3-1wt%In2O3-1wt%Nb2O5 sensor. With 100 ppb NO gas, the WO3-1wt%In2O3-1wt%Nb2O5 sensor achieved a high response of 56.1 at 70 °C, which is a state-of-the-art performance for NO detection at low working temperature settings. WO3-1wt%In2O3-1wt%Nb2O5 also yields significantly improved selectivity and stability over intrinsic WO3, WO3-In2O3, and WO3-Nb2O5. Studies on the sensing mechanism show that the grain size, rather than the n?n heterostructure effect, plays a dominant role in the observed results. By decreasing the grain size so that it is close to the thickness of the space-charge layer, the sensing response is enhanced. Although room remains to further improve the sensing properties, the performance of WO3-1wt%In2O3-1wt%Nb2O5 is sufficient for implementation in low-content NO detection devices.
关键词： codoping,high selectivity,NO gas sensor,limit of detection (LOD),ppb-level response,pulsed laser deposition (PLD)
更新于2025-09-09 09:28:46
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Diode Parameters of Heterojunctions Comprising <i>p</i> -Type Ultrananocrystalline Diamond Films and <i>n</i> -Type Si Substrates
摘要： In the current research, heterojunctions comprising p-type ultrananocrystalline diamond/hydrogenated amorphous carbon composite (UNCD/a-C:H) films and n-type Si substrates were formed via pulsed laser deposition. To extract their junction parameters via thermionic emission (TE) theory and Norde model, the measurement of dark current density–voltage curves was carried out under various temperatures ranging from 300 to 60 K. Through TE theory, the ideality factor values at 300 K and 60 K were 2.70 and 8.66, respectively. This justified that a heavy recombination process occurs at the junction interface in addition to another tunneling process at 300 K. The tunneling process is predominant at low temperatures. The barrier height values were 0.78 eV and 0.18 eV at 300 K and 60 K, respectively. The values for series resistance (Rs) at 300 K and 60 K were 275.24 Ω and 78.66 kΩ, respectively. The increment of Rs at low temperatures was likely due to the decrease of carrier concentration in the B-doped UNCD/a-C:H films when temperature was decreased.
关键词： PLD,Thin Films,UNCD/a-C:H,Heterojunction,Junction Parameters
更新于2025-09-09 09:28:46
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PLD fabrication of oriented nanowires in magnetic field
摘要： This paper presents an experimental investigation on laser-assisted fabrication of oriented nanowires composed by magnetic nanoparticles. The nanowires were produced by implementation of pulsed laser deposition in presence of a magnetic field. The application of an external magnetic field led to the formation of nanowires with a length of several micrometers whose orientation is influenced by the direction of the magnetic field lines. The influence of the type of ambient gas and its pressure on morphology and phase composition of the deposited samples was investigated. It was found that the ambient gas has direct influence on both the degree of orientation and the phase composition of the nanowires. SEM analysis of samples deposited at different target-substrate distances showed that the density of the nanowires decreases with the increase of the distance. A preliminary result on the magnetic properties of the produced nanowires is also reported.
关键词： Magnetic field,Iron oxide,Nanowires,PLD
更新于2025-09-09 09:28:46