Photo-activity and low resistivity in N/Nb Co-doped TiO2 thin films by combinatorial AACVD

A combinatorial aerosol assisted chemical vapour deposition (cAACVD) cation–anion co-doping study has been undertaken for the first time, which investigates the interplay of nitrogen and niobium co-dopants and the resultant functional properties within TiO2 thin films. This study advantageously creates a single doped TiO2 thin film which incorporates many compositions that transition from nitrogen doped TiO2 to niobium doped TiO2 across the film's width, in a single deposition. The film was split into a grid and the physical properties of each grid position characterised by X-Ray Diffraction (XRD), X-ray Photoelectron Spectroscopy (XPS), Scanning Electron Microscopy (SEM) and UV-visible transmission spectroscopy (UV/Vis). Functional properties such as photo-catalytic activity, water contact angles and resistivity were also characterised. The study was successful in creating and identifying the optimum dopant concentration at which these TiO2 films exhibited both a high rate of photo-activity and favourable transparent conducting oxide (TCO) properties. Whilst most co-doping studies report relatively homogenous film, the inhomogeneity of these films allows both functional properties to exist in conjunction. To the authors knowledge this is the first instance cation and anion co-doping has been explored in the combinatorial regime

A single-source precursor approach to solution processed indium arsenide thin films

This paper reports the synthesis of the novel single-source precursor, [{(MeInAstBu)3}2(Me2InAs(tBu)H)2] and the subsequent first report of aerosol-assisted chemical vapour deposition of InAs thin films. Owing to the use of the single-source precursor, highly crystalline and stoichiometric films were grown at a relatively low deposition temperature of 450 °C. Core level XPS depth profiling studies showed some partial oxidation of the film surface, however this was self-limiting and disappeared on etch profiles. Valence band XPS analysis matched well with the simulated density of state spectrum. Hall effect measurements performed on the films showed that the films were n-type with promising resistivity (3.6 × 10−3 Ω cm) and carrier mobility (410 cm2 V−1 s−1) values despite growth on amorphous glass substrates

Современные концепции управления высшим учебным заведением

Целью и задачами статьи является исследование современных подходов к управлению вузом, их критический анализ и возможность оптимизации процессов деятельности вуза

The use of time resolved aerosol assisted chemical vapour deposition in mapping metal oxide thin film growth and fine tuning functional properties

Time resolved analysis of a thin film has allowed, for the first time, analysis of how thin film growth occurs and changes over time by aerosol assisted CVD. This method has also allowed tuning of the materials' functional properties. In this report a hydrophobic and highly photocatalytic TiO2/SnO2 system is studied, which exhibits surface segregation of SnO2 and thus the novel formation of a natural hetero-junction charge transfer system. The time resolved samples were investigated by a variety of methods. The films were characterised by X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM) and Ultraviolet-visible absorption spectroscopy (UV-vis). Functional properties were investigated by photo-activity measurements and water contact angles before and after UV irradiation. The generation of representative samples at different times during the deposition sequence permitted changes in crystal structure, relative concentrations of atoms, and surface morphology to be linked intrinsically to changes in functional properties

Tungsten Doped TiO2 with Enhanced Photocatalytic and Optoelectrical Properties via Aerosol Assisted Chemical Vapor Deposition

Tungsten doped titanium dioxide films with both transparent conducting oxide (TCO) and photocatalytic properties were produced via aerosol-assisted chemical vapor deposition of titanium ethoxide and dopant concentrations of tungsten ethoxide at 500 °C from a toluene solution. The films were anatase TiO2, with good n-type electrical conductivities as determined via Hall effect measurements. The film doped with 2.25 at.% W showed the lowest resistivity at 0.034 Ω.cm and respectable charge carrier mobility (14.9 cm(3)/V.s) and concentration (×10(19) cm(-3)). XPS indicated the presence of both W(6+) and W(4+) in the TiO2 matrix, with the substitutional doping of W(4+) inducing an expansion of the anatase unit cell as determined by XRD. The films also showed good photocatalytic activity under UV-light illumination, with degradation of resazurin redox dye at a higher rate than with undoped TiO2

Dopant stability in multifunctional doped TiO 2's under environmental UVA exposure

We present a UV irradiation study of three nanomaterials which have been investigated and published by peer review previously, specifically tantalum, tungsten and phosphorus doped TiO2. These nanomaterials have been previously synthesised, characterised and designed with specific applications in mind, from photo-catalysts to transparent conducting oxides (TCO's) for use in solar cells and touchscreens. We show in this work, using X-ray photoelectron spectroscopy (XPS) that under sustained levels of environmental UVA Irradiation (0.42 mW cm−2) Ta5+ and W6+ substitutional doped TiO2 exhibits little to no variation in dopant concentration and distribution as a function of irradiation time. Interestingly P5+ and P3− co-doped TiO2 experiences a pronounced and nuanced change in dopant distribution and concentration across the surface through to the bulk as a function of irradiation time. Combined with our previous work with nitrogen doped TiO2, whereby 28 days of environmental UVA irradiation causes interstitial dopant loss and the attrition of functional properties, these results demonstrate that much is still to be understood regarding dopant stability in metal oxides such as TiO2 under environmental conditions

Chemical Vapor Deposition Synthesis and Optical Properties of Nb2O5 thin films with Hybrid Functional Theoretical Insight into Band Structure and Band Gaps

Nb2O5 is an important material able to exist in many polymorphs with unique optical properties and morphologies that are dependent on the synthetic route. Here we report a novel ambient-pressure chemical vapor deposition route to Nb2O5 via aerosol-assisted chemical vapor deposition. The amorphous as-deposited films were annealed in air to obtain the the three most stable crystal structures: orthorhombic, tetragonal, and monoclinic. The films were thoroughly characterized for their material properties, and an in-depth study into the optical properties was carried out using state-of-the-art hybrid functional theory that allowed more insight into the optical properties of the materials

Synthesis optimization of carbon-supported ZrO2 nanoparticles from different organometallic precursors

We report here the synthesis of carbon-supported ZrO2 nanoparticles from zirconium oxyphthalocyanine (ZrOPc) and acetylacetonate [Zr(acac)4]. Using thermogravimetric analysis (TGA) coupled with mass spectrometry (MS), we could investigate the thermal decomposition behavior of the chosen precursors. According to those results, we chose the heat treatment temperatures (THT) using partial oxidizing (PO) and reducing (RED) atmosphere. By X-ray diffraction we detected structure and size of the nanoparticles; the size was further confirmed by transmission electron microscopy. ZrO2 formation happens at lower temperature with Zr(acac)4 than with ZrOPc, due to the lower thermal stability and a higher oxygen amount in Zr(acac)4. Using ZrOPc at THT C900 °C, PO conditions facilitate the crystallite growth and formation of distinct tetragonal ZrO2, while with Zr(acac)4 a distinct tetragonal ZrO2 phase is observed already at THT C750 °C in both RED and PO conditions. Tuning of ZrO2 nanocrystallite size from 5 to 9 nm by varying the precursor loading is also demonstrated. The chemical state of zirconium was analyzed by X-ray photoelectron spectroscopy, which confirms ZrO2 formation from different synthesis routes

Improving the Performance in Occupational Health and Safety Management in the Electric Sector: An Integrated Methodology Using Fuzzy Multicriteria Approach

The electric sector is fundamental for the economic and social development of society, impacting on essential aspects such as health, education, employment generation, industrial production, and the provision of various services. In addition to the above, the growing trend in energy consumption worldwide could increase, according to expert estimates, up to 40% by 2030, which in turn increases the efforts of the public and private sector to meet increasing demands and increase access to energy services under requirements of reliability and quality. However, the electricity sector presents challenges and complexities, one of which is the reduction of health and safety risks for workers, service users, and other stakeholders. In many countries, this sector is classified as high risk in occupational safety and health, due to its complexity and the impact of accidents and occupational diseases on the health of workers, in infrastructure, in operating costs and competitiveness of the energy sector. Worldwide, there are rigorous regulations for the electricity sector, from local and national government regulations to international standards to guarantee health and safety conditions. However, it is necessary to develop objective and comprehensive methodologies for evaluating occupational safety and health performance that provides solutions for the electricity sector, not only to comply with standards and regulations also as a continuous improvement tool that supports the decision-making processes given the complexity of the industry and the multiple criteria that are taken into account when evaluating and establishing improvement strategies. In scientific literature, different studies focus on the analysis of accident statistics, the factors that affect accidents and occupational diseases, and the risk assessment of the sector. Despite these considerations, studies that focus directly on the development of hybrid methodologies for the evaluation and improvement of performance in occupational safety and health in the electrical sector, under multiple criteria and uncertainty are mostly limited. Therefore, this document presents an integrated methodology for improving the performance in occupational health and safety in the electric sector through the application of two techniques of Multi-criteria Decision Methods (MCDM) uses in environments under uncertainly. First, the fuzzy Analytic Hierarchy Process (FAHP) is applied to estimate the initial relative weights of criteria and sub-criteria. The fuzzy set theory is incorporated to represent the uncertainty of decision-makers’ preferences. Then, the Decision-making Trial and Evaluation Laboratory (DEMATEL) used for evaluating the interrelations and feedback among criteria and sub-criteria. FAHP and DEMATEL are later combined for calculating the final criteria and sub-criteria weights under vagueness and interdependence. Subsequently, we applied the proposed methodology in a company of the energy sector for diagnosis of performance in OHS to establish improvement proposals, the work path, and implementation costs. Finally, we evaluate the impact of the strategies applied in the improvement of the performance of the company

Contextual Factors and Challenges Affecting SMEs’ Access to Bank Finance and Performance: An Empirical Investigation into the Case of Saudi Arabia

Small and medium enterprises (SMEs) play a vital role in the modern economic system in providing alternative employment opportunities to the unemployed and efficiently and cost-effectively contributing to countries' economies. Over the years, SMEs have been acknowledged as substantial contributors to the economic growth of countries around the globe, providing a foundational platform for innovation in various business sectors. In the context of Saudi Arabia, SMEs comprise a more significant proportion of business enterprises operating in Saudi Arabia than large corporations. Nonetheless, SMEs face numerous challenges that limit their performance and growth. The most significant challenge remains financing. The availability of capital is a crucial element influencing the success or failure of any enterprise, whether large or small. SMEs being small and vulnerable to internal and external shocks pose a higher risk to external lenders. Hence, their access to timely and sufficient finance is a significant obstacle for their long-term sustainability and growth, particularly in developing countries such as Saudi Arabia. SMEs require access to external funding to have enough capital and financial resources to sustain their operations, fuel their growth and accomplish a higher performance. Despite the high significance of this particular business sector for the country's economic growth and its crucial relevance to the success of the country's Vision 2030, little empirical research, if any, particularly at the detailed exploratory level, has been devoted to exploring issues that are crucial to the sector's survival and sustainability. This current research project is a step in this direction, examining the factors that affect SMEs' accessibility to external bank financing and the impact of the same on their sustainability and performance. The research also investigates the challenges confronting SMEs s in Saudi Arabia and the lending criteria and requirements for small businesses imposed by banks and other financial institutions. The study also analyses the mediating influence of SME governance on the negative or positive appraisal of eligibility for funding for SMEs by government agencies in Saudi Arabia. The study identified six broad factors that affect SME's accessibility to bank financing—entrepreneurship factors, cultural factors, firm characteristics, banks' evaluation of SMEs eligibility for funding, SME governance and characteristics of financial information. The study's primary data utilises a concomitant triangulation design combining qualitative and quantitative techniques. This technique aims to gather extensive feasible data while simultaneously providing support to both qualitative and quantitative data. These data were collected using a survey conducted via questionnaires from 688 SMEs in Saudi Arabia and interviews with 20 business owners/managers of SMEs, 12 credit officers of banks and five members of government organisations in Saudi Arabia. Under the mixed methods approach, both quantitative and qualitative data were crucial for the researcher to explore and comprehensively understand and explore the research problem, given the diversity of the sample, which consisted mainly of SME managers/owners, government agencies and bank credit managers, as well as the scope and focus of the topic under investigation. Resorting to the qualitative method helped the researcher interact closely with the study participants and explore and understand the statistically quantifiable relationships among the study variables. Conversely, the quantitative approach helped measure the following eight sample variables in the light of the study objectives: firm characteristics, financial information characteristics, cultural factors, entrepreneurship factors, banks' evaluation of SMEs, obtaining finance, SME governance and firm performance. This current study results revealed that access to financing continues to be the major challenge facing small- and medium-sized businesses in Saudi Arabia. The results also show that most SMEs' owners/managers failed to receive funding from Saudi banks for several reasons, including lack of adequate collateral to secure the banks' position, poor financial performance, unfeasible business strategies, insufficient information and business ventures that did not qualify for financing from financial institutions. The study outcomes also revealed that the banks relied heavily on governmental help and support to fund SMEs. Consequently, specialised government agencies were more compatible with SMEs' peculiar operational and structural requirements than banks. The study revealed that government institutions need more regulations to develop the SME sector. Further, since SMEs rely primarily on the acquisition of capital from limited internal sources of funding rather than external sources, factors affecting their funding are crucial to their efficiency and performance. The study revealed that cultural factors affected firm characteristics and entrepreneurship factors on characteristics of SMEs' financial information. Moreover, the cultural factor, the entrepreneurship factor and the characteristics of SMEs' financial information directly affected banks' evaluation of SMEs' eligibility for funding. The firm characteristics, the characteristic of SMEs' financial information, and banks' evaluation of SMEs had substantial direct effect on SMEs financing, the study results further revealed. SMEs' performance had a significant direct affect from the level and extent of their access to banks' financing. In addition, the research results also displayed a significant level of positive mediating effect on the banks' evaluation of SMEs' eligibility for and access to finance by the SME governance, which serve as intermediaries in financing negotiations between two stakeholders. This current research is timely, relevant and first of its kind in the context of Saudi Arabia because it aims to address pertinent issues in connection to the sector's financial challenges and limitations to access bank finance while the country is pursuing its Vision 2030, under which diversification of its economy with a more market-oriented focus and elimination of its overdependence on the oil and gas sector are the primary goals the government has set. The study will assist Saudi Arabia to better understand and efficiently tackle the current financing problems confronting SMEs. The study provides crucial insights into the characteristic of SMEs in Saudi Arabia and the internal and external factors that play a role in limiting their access to bank finances, highlighting the critical role of governments and financial institutions in providing easier and achievable financial access to SMEs. The conceptual framework developed as part of the research endeavour shows how governments and financial institutions can implement workable solutions to improve SMEs' access to financial help. The research findings indicate the existence of a significant 'SME financial gap' in the context of Saudi Arabia, despite the government's efforts to make funding accessible to the country's SME industry. The SME funding model the study puts forth will significantly improve SMEs' access to bank finance by streamlining financial processes and services in lending institutions to better suit the peculiar needs of the country's SMEs. The above findings concluded the research project with implications for academics, practitioners and policymakers in Saudi Arabia. Further, it provides recommendations for a dedicated support package that would ensure the growth and improvement of SMEs in Saudi Arabia and promote their access to bank finance through the facilitation by all stakeholders of a trustful relationship between SMEs and financial institutions. Finally, suggestions for future empirical research in closely related areas are made to the benefit the sector, particularly as the country approaches the culmination of its Vision 2030 and beyond