Abstract:Metal-oxide thin
films find many uses in (opto)electronic and renewable
energy technologies. Their deposition by solution methods aims to
reduce manufacturing costs relative to vacuum deposition while achieving
comparable electronic properties. Solution deposition on temperature-sensitive
substrates (e.g., plastics), however, remains difficult due to the
need to produce dense films with minimal thermal input. Here, we investigate
combustion thin-film deposition, which has been proposed to produce
high-quality… Show more
“…The answer to this question would enable the researcher to determine, for example, what types of substrates could be layered with a metal coating of certain conductivity. We therefore leveraged Ada to effectively study the numerous compositional 47 , 48 and processing variables 43 , 49 that influence processing temperatures and the corresponding conductivities. Fig.…”
Useful materials must satisfy multiple objectives, where the optimization of one objective is often at the expense of another. The Pareto front reports the optimal trade-offs between these conflicting objectives. Here we use a self-driving laboratory, Ada, to define the Pareto front of conductivities and processing temperatures for palladium films formed by combustion synthesis. Ada discovers new synthesis conditions that yield metallic films at lower processing temperatures (below 200 °C) relative to the prior art for this technique (250 °C). This temperature difference makes possible the coating of different commodity plastic materials (e.g., Nafion, polyethersulfone). These combustion synthesis conditions enable us to to spray coat uniform palladium films with moderate conductivity (1.1 × 105 S m−1) at 191 °C. Spray coating at 226 °C yields films with conductivities (2.0 × 106 S m−1) comparable to those of sputtered films (2.0 to 5.8 × 106 S m−1). This work shows how a self-driving laboratoy can discover materials that provide optimal trade-offs between conflicting objectives.
“…The answer to this question would enable the researcher to determine, for example, what types of substrates could be layered with a metal coating of certain conductivity. We therefore leveraged Ada to effectively study the numerous compositional 47 , 48 and processing variables 43 , 49 that influence processing temperatures and the corresponding conductivities. Fig.…”
Useful materials must satisfy multiple objectives, where the optimization of one objective is often at the expense of another. The Pareto front reports the optimal trade-offs between these conflicting objectives. Here we use a self-driving laboratory, Ada, to define the Pareto front of conductivities and processing temperatures for palladium films formed by combustion synthesis. Ada discovers new synthesis conditions that yield metallic films at lower processing temperatures (below 200 °C) relative to the prior art for this technique (250 °C). This temperature difference makes possible the coating of different commodity plastic materials (e.g., Nafion, polyethersulfone). These combustion synthesis conditions enable us to to spray coat uniform palladium films with moderate conductivity (1.1 × 105 S m−1) at 191 °C. Spray coating at 226 °C yields films with conductivities (2.0 × 106 S m−1) comparable to those of sputtered films (2.0 to 5.8 × 106 S m−1). This work shows how a self-driving laboratoy can discover materials that provide optimal trade-offs between conflicting objectives.
“…Figure 1a shows the thermal analysis of the combustible precursors using thermogravimetric analysis (TGA) and differential thermal analysis (DTA), along with the first derivative of TGA, which indicates that the combustible precursor undergoes an exothermic reaction. Although the use of bulk precursor thermal analysis for predicting the thermal decomposition of precursor thin films is debatable, [24,34] it provides an initial rough estimation of the minimum temperature and/or annealing temperature (T a ) at which the product-metal oxide forms. Owing to the large surface-to-volume ratio of the deposited thin films with thickness in the range of nanometers, the required T a is comparatively lower than the magnitude predicted from the bulk precursor thermal analysis.…”
The fabrication of Hf 0.5 Zr 0.5 O 2 -ferroelectric negative capacitor using solution combustion is presented for the first time. The starting materials used for the solution combustion to form equimolar Hf 0.5 Zr 0.5 O 2 are to act as both combustible elements and cation sources. Jain's method, which is used for estimating the stoichiometric quantities of precursors in propellant chemistry, has also been modified and applied. The conventional assumption for this method that molecular oxygen does not take part in the reaction is refuted and stoichiometric combustion in the presence of molecular oxygen is proposed. This reaction is followed by post-rapid thermal processing to stabilize the metastable, non-centrosymmetric orthorhombic phase. The thin film stacks, Hf 0.5 Zr 0.5 O 2 /HfO 2 , are used to achieve sub-thermionic swing (forward sweep: 25.42 ± 8.05 mV dec −1 , reverse sweep: 42.56 ± 4.87 mV dec −1 ) in MoS 2 negative capacitance field effect transistors with a hysteresis of ≈40 mV at 1 nA, resulting in ultra-low-power operation.
“…This is expected to have a two-fold influence on the microstructural evolution in the multilayered thin films, as schematically shown in Fig 6b. Firstly, it enables a more efficient removal of the gaseous products from the inner part of the films in the case of thinner layers, resulting in lower porosity (see Fig.3b). Secondly, a faster removal of the gas will result in increased kinetics of the combustion reaction 50 and an increased amount of released heat in a shorter amount of time, which results in larger grain size and improved crystallinity of the final films (see Fig. 2b).…”
Combustion synthesis is a well-known method for synthesis of transparent metal oxide thin films at low temperature (< 400 oC). However, their functional properties are often inferior due to high...
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