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On the Effect of Thin Film Growth Mechanisms on the Specular Reflectance of Aluminium Thin Films Deposited via Filtered Cathodic Vacuum Arc
摘要： The optimisation of the specular reflectance of solar collectors is a key parameter to increase the global yield of concentrated solar power (CSP) plants. In this work, the influence of filtered cathodic vacuum arc deposition parameters, particularly working pressure and deposition time, on the specular and diffuse reflectance of aluminium thin films, was studied. Changes in specular reflectance, measured by ultraviolet–visible and near-infrared spectroscopy (UV-vis-NIR) spectrophotometry, were directly correlated with thin film elemental concentration depth profiles, obtained by Rutherford backscattering spectrometry (RBS), and surface and cross-sectional morphologies as measured by scanning electron microscopy (SEM) and profilometry. Finally, atomic force microscopy (AFM) provided information on the roughness and growth mechanism of the films. The two contributions to the total reflectance of the films, namely diffuse and specular reflectance, were found to be deeply influenced by deposition conditions. It was proven that working pressure and deposition time directly determine the predominant factor. Specular reflectance varied from 12 to 99.8% of the total reflectance for films grown at the same working pressure of 0.1 Pa and with different deposition times. This transformation could not be attributed to an oxidation of the films as stated by RBS, but was correlated with a progressive modification of the roughness, surface, and bulk morphology of the samples over the deposition time. Hence, the evolution in the final optical properties of the films is driven by different growth mechanisms and the resulting microstructures. In addition to the originally addressed CSP applications the potential of the developed aluminium films for other application rather than CSP, such as, for example, reference material for spectroscopic diffuse reflectance measurements, is also discussed.
关键词： structural characterisation,total and specular reflectance,filtered cathodic vacuum arc,thin film deposition conditions
更新于2025-10-22 19:40:53
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Low-Temperature Plasma-Enhanced Atomic Layer Deposition of Tin(IV) Oxide from a Functionalized Alkyl Precursor: Fabrication and Evaluation of SnO <sub/>2</sub> -Based Thin-Film Transistor Devices
摘要： A bottom-up process from precursor development for tin to plasma-enhanced atomic layer deposition (PEALD) for tin(IV) oxide and its successful implementation in a working thin-film transistor device is reported. PEALD of tin(IV) oxide thin films at low temperatures down to 60 °C employing tetrakis-(dimethylamino)propyl tin(IV) [Sn(DMP)4] and oxygen plasma is demonstrated. The liquid precursor has been synthesized and thoroughly characterized with thermogravimetric analyses, revealing sufficient volatility and long-term thermal stability. [Sn(DMP)4] demonstrates typical saturation behavior and constant growth rates of 0.27 or 0.42 ? cycle?1 at 150 and 60 °C, respectively, in PEALD experiments. Within the ALD regime, the films are smooth, uniform, and of high purity. On the basis of these promising features, the PEALD process was optimized wherein a 6 nm thick tin oxide channel material layer deposited at 60 °C was applied in bottom-contact bottom-gate thin-film transistors, showing a remarkable on/off ratio of 107 and field-effect mobility of ≈ 12 cm2 V?1 s?1 for the as-deposited thin films deposited at such low temperatures.
关键词： thin-film transistors,tin(IV) oxide,thin films,precursors,atomic layer deposition
更新于2025-09-23 15:23:52
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Elucidating the Exceptional Passivation Effect of 0.8 nm Evaporated Aluminium on Transparent Copper Films
摘要： Slab-like copper films with a thickness of 9 nm (～70 atoms) and sheet resistance of ≤9 Ω sq?1 are shown to exhibit remarkable long-term stability toward air-oxidation when passivated with an 0.8 nm aluminium layer deposited by simple thermal evaporation. The sheet resistance of 9 nm Cu films passivated in this way, and lithographically patterned with a dense array of ～6 million apertures per cm2, increases by <3.5% after 7,000 h exposure to ambient air. Using a combination of annular-dark field scanning transmission electron microscopy, nanoscale spatially resolved elemental analysis and atomic force microscopy, we show that this surprising effectiveness of this layer results from spontaneous segregation of the aluminium to grain boundaries in the copper film where it forms a ternary oxide plug at those sites in the metal film most vulnerable to oxidation. Crucially, the heterogeneous distribution of this passivating oxide layer combined with its very low thickness ensures that the underlying metal is not electrically isolated, and so this simple passivation step renders Cu films stable enough to compete with Ag as the base metal for transparent electrode applications in emerging optoelectronic devices.
关键词： passivation,thin film,transparent electrode,lithography,copper
更新于2025-09-23 15:23:52
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[IEEE 2018 IEEE 7th World Conference on Photovoltaic Energy Conversion (WCPEC) (A Joint Conference of 45th IEEE PVSC, 28th PVSEC & 34th EU PVSEC) - Waikoloa Village, HI, USA (2018.6.10-2018.6.15)] 2018 IEEE 7th World Conference on Photovoltaic Energy Conversion (WCPEC) (A Joint Conference of 45th IEEE PVSC, 28th PVSEC & 34th EU PVSEC) - Commercial Test of Anti-Reflective Coating on First Solar Cadmium Telluride PV Modules
摘要： Anti-reflective coatings (ARC) are commonly applied to photovoltaic (PV) modules in the solar industry to increase power and energy output. In addition to characterization of initial module power and angle of incidence modifier (IAM), it is important to verify that the expected gain is observed in commercial system operation. This analysis shows the increased performance of ARC First Solar CdTe PV modules compared to non-ARC equivalent modules in a commercial test in New South Wales, Australia. PPI analysis indicates a sustained ARC performance gain over time, suggesting good ARC durability. Detailed actual-expected analysis shows both array types performing at or above expected levels after almost 2 years in the field. ARC arrays show slightly greater benefit than predicted compared to non-ARC arrays.
关键词： CdTe thin film photovoltaics,solar power generation,performance analysis,photovoltaic systems,PV anti-reflective coatings,solar energy
更新于2025-09-23 15:23:52
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Sol–Gel Spin-Coating Followed by Solvothermal Synthesis of Nanorods-Based ZnO Thin Films: Microstructural, Optical, and Gas Sensing Properties
摘要： Zinc oxide thin films with nanorod morphology were investigated for microstructural and optical properties as well as their performance as a liquid petroleum gas sensing material. A two-step synthesis procedure consisting of sol–gel spin-coating and solvothermal methods was employed where several factors such as rational utilization of metal precursors, solvent, stabilizing, and structure directing agents, a repetitive drying-coating process, as well as post-thermal annealing were found influential to obtain qualified nanorods and a final homogeneous thin film. Compositional and optical investigations were pursued to characterize features, namely morphology, poly crystallinity, porous structure, nanocrystallite size, lattice oriented growth, textural atomic ratio, lattice purity and transparency, phonon and exciton transitions, as well as the formed structural defects via field-emission scanning electron microscopy, x-ray diffraction, energy-dispersive x-ray, UV–Vis spectroscopy, Raman, and photoluminescence techniques. The as-prepared thin film was then used as an active LPG sensing material via a home-made gas sensor where the control sensing parameters were chamber testing temperature and gas concentration. Results showed a quantitative response of 92.7% as sensor sensitivity at an operation temperature of 250°C and a LPG concentration of 800 ppm in addition to fast response and recovery times of 44.1 s and 218.7 s, respectively.
关键词： Zinc oxide nanorods,thin film,optical characteristics,gas sensing,microstructural properties,liquid petroleum gas
更新于2025-09-23 15:23:52
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Optical Properties of Nanohole Arrays with Various Depths
摘要： Studies to imitate structural colors have been conducted with various methods, most of which are disadvantageous for mechanical stability and economic feasibility because of complexity or lack of reproducibility. Numerous alternatives to overcome these shortcomings have been proposed. One such method is the anodic oxidation of aluminum, which requires relatively simple equipment and techniques. The present study used the aluminum anodic oxidation process to fabricate nanohole arrays of various sizes. Furthermore, using the finding that the structure color is the most strongly influenced by the nanohole depth based on the Bragg's Law, this study fabricated nanoholes of various depths to identify the structural colors arising from varied depths. This study further identified the colors from the same color series occurring periodically at each interval of 250 nm using the CIE 1931 color coordinate system. Moreover, nanohole arrays with two different depths were fabricated on a single substrate to confirm the coexistence of different colors and their capacity for deformation into various shapes.
关键词： Nanohole array,Structural color,Bragg's law,Anodic aluminum oxidation,Thin film effect
更新于2025-09-23 15:23:52
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Tailoring metal film texture by use of high atomic mobility at metal-semiconductor interfaces
摘要： The difference in the microstructural and texture evolution of Al films grown on amorphous SiO2 (a-SiO2) and amorphous Ge (a-Ge) substrates have been investigated. Surprisingly, the a-Ge substrate was found to change the preferred orientation of Al grains from the conventional (1 1 1) to the unconventional (1 1 0). The effect of the high mobility of Ge atoms at the metal-semiconductor interface on the microstructural and texture evolution of the metal thin film was studied. The diffusion of the Al adatoms on the a-Ge substrate was suppressed owing to the segregation of Ge atoms at the film surface. The mobility of Al grain boundaries was also suppressed because of grain-boundary wetting by the Ge atoms. It is concluded that the a-Ge substrate could tailor the Al grain orientation from (1 1 1) to (1 1 0) owing to the change in the film-growth mode from three-dimensional to two-dimensional nucleation. The concept of interaction-induced island-growth model, which is based on the Volmer–Weber growth model, is also discussed here. This work thus demonstrates how the atomic mobility at the interface of the metal thin film and the semiconductor substrate controls the film microstructure and texture during deposition.
关键词： Substrate,Microstructure,Surface diffusion,Texture,Metal thin film,Grain-boundary wetting
更新于2025-09-23 15:23:52
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Preparation of high-quality stress-free (001) aluminum nitride thin film using a dual Kaufman ion-beam source setup
摘要： We proposed and demonstrated a preparation method of (001) preferentially oriented stress-free AlN piezoelectric thin films. The AlN thin films were deposited by a reactive sputtering technique at substrate temperatures up to 330 °C using a dual Kaufman ion-beam source setup. We deposited the AlN on Si (100), Si (111), amorphous SiO2, and a (001) preferentially oriented Ti thin film and compared their crystallographic, optical, and piezoelectric properties. The AlN thin films deposited on the (001) preferentially oriented Ti thin films have the highest crystallographic quality. The stress-free AlN reached a high value of the piezoelectric coefficient d33 = (7.33 ± 0.08) pC·N?1. The properties of the AlN thin film prepared at such low temperatures are suitable for numerous microelectromechanical systems, piezoelectric sensors, and actuators monolithically integrated with complementary metal-oxide-semiconductor signal-processing circuits.
关键词： Ellipsometry,Aluminum nitride thin film,Optical properties,d33 piezoelectric coefficient,Kaufman ion-beam source,Ion-beam sputtering deposition,(001) preferential orientation,X-ray diffraction
更新于2025-09-23 15:23:52
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Diketopyrrolopyrrole based small molecular semiconductors containing thiazole units for solution-processed n-channel thin-film transistors
摘要： In this work, three diketopyrrolopyrrole-based conjugated small molecular semiconductors characterized by the combination of a diketopyrrolopyrrole (DPP) central core, thiazole π-conjugated moiety, and dicyanovinyl end group with different alkyl side chain substituents, 2TzDPPA1-2DCV, 2TzDPPA2-2DCV, and 2TzDPPA3-2DCV were synthesized. These small molecules have a similar narrow band gap of about 1.50 eV and deep LUMO energy level at -4.30 eV. Under ambient conditions, electron mobilities of 0.28 cm2 V-1 s-1, 0.13 cm2 V-1 s-1, 0.25 cm2 V-1 s-1 for solution processed thin films of 2TzDPPA1-2DCV, 2TzDPPA2-2DCV, and 2TzDPPA3-2DCV were obtained, due to high crystallinity and well-organized molecular stacking. Compared with the other two materials, thin films of 2TzDPPA1-2DCV enable the best OFET performance with desirable Ion / Ioff rates exceeding of 107, attribute to the coefficient of smoother film morphology and stronger crystallinity. These results reveal that introducing the thiazole unit into the DPP-based conjugated skeleton is conducive to enhance the crystallinity and tailor LUMO energy levels which ensure good performance and excellent stability of these molecules as active materials for n-channel electronic devices.
关键词： small molecules,solution-processed n-channel thin-film transistors,thiazole unit,diketopyrrolopyrrole,air stability
更新于2025-09-23 15:23:52
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24.5: Back-Channel-Etched a-IGZO TFTs with TiO <sub/>2</sub> :Nb Protective Layer
摘要： A back-channel-etched (BCE) process for the fabrication of a-IGZO TFTs is demonstrated, in which conductive TiO2:Nb (TNO) thin film is used to serve as protective layer for the a-IGZO active layer. TNO film could excellently protect a-IGZO due to its ultra-small surface roughness. With treatment by N2O plasma + 200°C annealing, the conductive TNO can be converted into an insulator to serve as an in situ passivation layer. Besides, the TNO in the source–drain (S-D) region remain conductive due to the protection of S-D electrodes, which could be proved by the XPS results. Compare with the conventional device without TNO protective layer, the S-D parasitic resistance (RSD) of devices with 1 nm and 5 nm TNO is significantly reduced. The positive bias stress stability is improved as well for the devices with TNO in situ passivation layer.
关键词： amorphous indium gallium zinc oxide (a-IGZO),Nb doped TiO2 (TNO),thin film transistors (TFTs),back-channel-etched (BCE) process
更新于2025-09-23 15:23:52