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Analysis of Cu doping concentration on PbS thin films for the fabrication of solar cell using feasible nebulizer spray pyrolysis
摘要： This report portrays the analysis of Cu doping concentration (%) on PbS thin films prepared by feasible nebulizer spray technique. The doping percentage of Cu was increased from 0% to 8% in steps of 2%. X-ray diffraction study of the films evinces the nature of the films as polycrystalline with simple cubic crystal structure. The calculated crystallite size was varied from 55 to 41 nm on increasing the Cu doping concentration. SEM/AFM studies proclaim that the cubic shaped grains have covered the entire film surface. The shape of grains was amended with respect to the increase in Cu doping concentration. An elevation in band gap from 1.61 eV to 2.10 eV was spotted for the raise in Cu doping concentration from 0% to 6%. The near band edge emission peak at 575 nm was sensed from PL spectra in which the intensity was enhanced. Hall Effect measurement declared the p-type conductivity nature for the prepared PbS films. Resistivity and carrier-concentration values are 0.73×103 Ωcm and 6.04×1013 cm-3 respectively for 6% Cu doped PbS thin films. Efficiency for the solar cell FTO/n-CdS/p-Cu:PbS structure constructed with 6% Cu doped PbS film is about 0.68%.
关键词： X-ray diffraction,PL spectra,Hall Effect measurement,AFM/SEM,Cu doped PbS film
更新于2025-11-21 11:18:25
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Multifunctional atomic force probes for Mn2+ doped perovskite solar cells
摘要： Doping in organic–inorganic perovskite semiconductors is an effective method to tailor their optoelectronic properties. In this work, manganese-doped perovskite films with different Mn/Pb ratios ranging from 0% to 2% were systematically studied. The device performance of 0.2% Mn-doped devices was improved compared to that of a device without Mn. However, a further increase of the doping concentration induced a decrease in performance. Several characteristics (especially different scanning probe microscopy characteristics) reveal that an increased dopant concentration results in reduced crystallinity and a change in the film morphology and causes a deterioration in photovoltaic performance for higher dopant concentrations. In the best-performing samples (0.2%), a shift in the valence band level and band gap are found which are responsible for the increased open circuit voltage, while increased grain boundaries and lower surface charge density are responsible for a small reduction in the short circuit current. Thus, multifunctional scanning probe microscopy approaches, combined with different film characterization techniques, offer us effective tools to investigate the impact of doping in the perovskite materials and the corresponding device performance.
关键词： EFM,SKPM,C-AFM,Perovskite solar cells
更新于2025-11-20 15:33:11
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High-Performance Photoresistors Based on Perovskite Thin Film with a High PbI2 Doping Level
摘要： We prepared high-performance photoresistors based on CH3NH3PbI3 ?lms with a high PbI2 doping level. The role of PbI2 in CH3NH3PbI3 perovskite thin ?lm was systematically investigated using scanning electron microscopy, X-ray diffraction, time-resolved photoluminescence spectroscopy, and photoconductive atomic force microscope. Laterally-structured photodetectors have been fabricated based on CH3NH3PbI3 perovskite thin ?lms deposited using precursor solution with various CH3NH3I:PbI2 ratios. Remarkably, the introduction of a suitable amount of PbI2 can signi?cantly improve the performance and stability of perovskite-based photoresistors, optoelectronic devices with ultrahigh photo-sensitivity, high current on/off ratio, fast photo response speed, and retarded decay. Speci?cally, a highest responsivity of 7.8 A/W and a speci?c detectivity of 2.1 × 1013 Jones with a rise time of 0.86 ms and a decay time of 1.5 ms have been achieved. In addition, the local dependence of photocurrent generation in perovskite thin ?lms was revealed by photoconductive atomic force microscopy, which provides direct evidence that the presence of PbI2 can effectively passivate the grain boundaries of CH3NH3PbI3 and assist the photocurrent transport more effectively.
关键词： grain boundary passivation,PC-AFM,photoresistor,high PbI2 doping content
更新于2025-11-14 15:28:36
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How to unravel the chemical structure and component localization of individual drug-loaded polymeric nanoparticles by using tapping AFM-IR
摘要： AFM-IR is a photothermal technique that combines AFM and infrared (IR) spectroscopy to unambiguously identify the chemical composition of a sample with tens of nanometer spatial resolution. So far, it has been successfully used in contact mode in a variety of applications. However, the contact mode is unsuitable for soft or loosely adhesive samples such as polymeric nanoparticles (NPs) of less than 200 nm of wide interest for biomedical applications. We describe here the theoretical basis of the innovative tapping AFM-IR mode that can address novel challenges in imaging and chemical mapping. The new method enables gaining information not only on NP morphology and composition, but also reveals drug location and core–shell structures. Whereas up to now the locations of NP components could only be hypothesized, tapping AFM-IR allows accurately visualizing both the location of the NPs’ shells and that of the incorporated drug, pipemidic acid. The preferential accumulation of the drug in the NPs’ top layers was proved, despite its low concentration (<1 wt%). These studies pave the way towards the use of tapping AFM-IR as a powerful tool to control the quality of NP formulations based on individual NP detection and component quantification.
关键词： tapping mode,chemical mapping,core–shell structure,drug localization,polymeric nanoparticles,AFM-IR
更新于2025-11-14 15:18:02
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Nano-Heteroepitaxy: An Investigation of SiGe Nano-Pillars Coalescence
摘要： In this paper, SiGe nano-pillars coalescence was investigated using industrial Reduced Pressure-Chemical Vapour Deposition integration scheme based on diblock copolymer patterning provided nanometer size templates for the selective epitaxy of SiGe 25% nano-pillars. In order to study merging, thicknesses ranging from 20 to 35 nm were grown and samples characterized by AFM, XRD, SSRM and TEM. The evolution in terms of grains shape, size and number was examined, with individual pillars merging into larger grains above 30 nm thickness. High degrees of macroscopic strain relaxation were obtained at the different stages of nano-pillars merging. Defects such as stacking faults and twins were identified as occurring at the early stages of nano-pillar coalescence.
关键词： SSRM,TEM,coalescence,AFM,SiGe nano-pillars,Reduced Pressure-Chemical Vapour Deposition,XRD
更新于2025-11-14 14:32:36
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Geometric parameters effect of the atomic force microscopy smart piezoelectric cantilever on the different rough surface topography quality by considering the capillary force
摘要： Nowadays, the atomic force microscopy (AFM) is widely used in the nanotechnology as a powerful nano-robot. The surface topography in Nanoscale is by far one of the most important usages of the AFM device. Hence, in this article, the vibration motion of a piezoelectric rectangular cross-section micro-cantilever (MC) which oscillates in the moist environment has been examined based on the Timoshenko beam theory. After extracting the MC governing equations according to Hamilton's principle, the finite element method has been used to discretize the motion equations. The surface topography has been simulated for various roughness forms in the tapping and non-contact modes by considering the effects of the Van der Waals, capillary and contact forces. Also, the experimental results obtained from the glass surface topography have been simulated. The results illustrate that the time delay in higher natural frequencies in the tapping mode is shorter in comparison with the non-contact mode, especially, for the lower natural frequencies. The sensitivity analysis of the natural frequencies, topography depth and time delay have been simulated. Results indicate that the most effective parameter is the MC length. In the first mode, the first section length has the highest effect on the surface topography time delay, also, in the second vibration mode; the most effective parameter on the time delay is the MC tip length based on the simulation results.
关键词： AFM piezoelectric micro-cantilever,Timoshenko beam,sensitivity analysis,finite element method,topography depth
更新于2025-09-23 15:23:52
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Determination of physical properties of graphene doped ZnO (ZnO:Gr) nanocomposite thin films deposited by a thermionic vacuum arc technique
摘要： This study is focused on the growth of graphene doped ZnO (ZnO:Gr) nanocomposite thin films by a thermionic vacuum arc (TVA) technique. ZnO:Gr nanocomposite thin films were deposited onto glass and silicon (Si) substrates. The influence of the dopant effect on structural, optical, morphological properties of the ZnO:Gr nanocomposite thin films were investigated by using various analysis techniques such as interferometer, UV-Visible spectrophotometer, X-ray diffraction (XRD), Raman spectrometer, Fourier Transform Infrared spectroscopy (FTIR), Photoluminescence (PL) spectroscopy, Field Emission Scanning Electron Microscopy (FESEM), and Atomic Force Microscopy (AFM). Thicknesses value of ZnO:Gr nanocomposite thin films for the deposited layers onto glass and Si substrates were measured as to be 50 nm and 20 nm, respectively. In XRD patterns, the reflections of the ZnO and carbon nanostructures were observed. Using UV–Vis spectrophotometer and optical interferometer, the refractive index, reflectance, transmittance, absorbance and optical band gap graphs of the ZnO:Gr nanocomposite thin films were determined. Optical band gap of the ZnO:Gr nanocomposite thin film that deposited on glass substrate was determined as to be 3.15 eV via optical method and the result is in good harmony with PL measurement. PL spectrum showed an ultraviolet (UV) emission peak at 397 nm (3.12 eV). From the Raman analysis of the ZnO:Gr nanocomposite thin films, ZnO, D and 2D peaks of the graphene were observed. FTIR spectroscopy was used to analyze the chemical composition of the samples. According to AFM and FESEM analysis, ZnO:Gr nanocomposite thin films are smooth, flat, granular, uniform and dense form. Due to the larger crystallite sizes ZnO:Gr nanocomposite thin film onto Si substrate has lower resistivity according to the ZnO:Gr nanocomposite thin film deposited onto glass substrate. As a result, ZnO:Gr nanocomposite thin films are promising material for potential applications as to be a transparent conducting oxide (TCO) material.
关键词： FESEM,TVA,ZnO:Gr nanocomposite thin films,XRD,AFM
更新于2025-09-23 15:23:52
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Evaluating Mechanical Properties of Polymers at the Nanoscale Level via Atomic Force Microscopy–Infrared Spectroscopy
摘要： Characterization and optimization of packaging materials requires accessing their composition with nanometric precision. A possible solution comes from AFM-IR, a technique based on the coupling of Atomic Force Microscope and InfraRed spectroscopy, capable to acquire IR spectra with a spatial resolution overpassing by far the limit of infrared spectroscopy. Differentiating polyolefins – typical component of packaging films – is complicated by the large similarity in the infrared response of this class of materials. Here, we propose a method to improve domains differentiation based on the analysis of IR spectra and viscoelastic properties, extracted via a routine similar to that employed in contact-resonance AFM.
关键词： Subdiffraction Resolution,Photothermal Induced Resonance.,AFM-IR,Polymers
更新于2025-09-23 15:23:52
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Multivariable study on growth of diamond on diamond substrates by microwave? plasma chemical vapour deposition
摘要： Substrate temperature and methane concentration in Hydrogen (H2) gas mixture is the main source for increasing the growth rate, nucleation and grain size of a synthetic diamond. The downside of such an approach is reduced quality. By increasing the chamber pressure, although the quality can be improved, however, it leads to a decrease in the crystal growth rate. Thin diamond films were deposited under hydrogen (H2) and methane (CH4) gas mixture using microwave plasma chemical vapor deposition (MPCVD) technique. The effect of methane concentration (1-5%), growth temperature, and pressure on the nucleation of diamond thin films on diamond substrates was investigated. The growth temperature and pressure were maintained in the range of 925-950 ℃ and 72-75 Torr, respectively. Single crystal diamond (SCD) thin films have been prepared on diamond substrates, which play an important role in the application of the diamond detectors. Different dimensions of films were obtained on diamond substrates with different thicknesses such as 209.17 μm, 401.73 μm, and 995.03μm for the sample with 1%, 2% and 5% of methane concentration respectively. The roughness, as well as growth rate of these films, were also investigated and were found to be 5.02 μ/h and 4.23 nm, respectively for 5% methane by optimizing the substrate temperature at 950 ℃. Different characterization techniques were used to study the structural, morphological, and compositional properties of the deposited diamond films which confirmed the crystallographic order of the developed diamond film on the diamond substrates.
关键词： MPCVD,XRD,Diamond thin films,XPS,Raman spectroscopy,AFM,SEM
更新于2025-09-23 15:23:52
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[IEEE 2018 IEEE 2nd International Conference on Dielectrics (ICD) - Budapest (2018.7.1-2018.7.5)] 2018 IEEE 2nd International Conference on Dielectrics (ICD) - Chemical Analysis of Solid Insulation Degradation using the AFM-IR Technique
摘要： To enable the continued development of power transmission cabling, an understanding of the processes which result in their failures is essential. In order to do so, powerful analysis techniques are required. However, those which consider chemical degradation are lagging behind those for visible degradation. This paper presents the Atomic Force Microscopy - Infrared Spectroscopy (AFM-IR) chemical analysis technique, which can provide surface chemical analysis with resolution of ~50 nm across the infrared spectrum. Two cases are considered: interfacial tracking between epoxy and silicone rubber, and the degraded region formed in front of a needle tip in the electrical tree initiation process. The results obtained using AFM-IR are compared to the outcomes from other techniques. It is found that AFM-IR offers a unique and powerful insight into visible and non-visible degradation of solid dielectrics.
关键词： AFM-IR,epoxy,chemical analysis,interfacial tracking,Electrical treeing,degradation
更新于2025-09-23 15:22:29