New deposition techniques for amorphous oxide semiconductors compatible with silicon back end of line manufacturing are needed for 3D monolithic integration of thin‐film electronics. Here, three atomic layer deposition (ALD) processes are compared for the fabrication of amorphous zinc tin oxide (ZTO) channels in bottom‐gate, top‐contact n‐channel transistors. As‐deposited ZTO films, made by ALD at 150–200 °C, exhibit semiconducting, enhancement‐mode behavior with electron mobility as high as 13 cm2 V−1 s−1, due to a low density of oxygen‐related defects. ZTO deposited at 200 °C using a hybrid thermal‐plasma ALD process with an optimal tin composition of 21%, post‐annealed at 400 °C, shows excellent performance with a record high mobility of 22.1 cm2 V–1 s–1 and a subthreshold slope of 0.29 V dec–1. Increasing the deposition temperature and performing post‐deposition anneals at 300–500 °C lead to an increased density of the X‐ray amorphous ZTO film, improving its electrical properties. By optimizing the ZTO active layer thickness and using a high‐k gate insulator (ALD Al2O3), the transistor switching voltage is lowered, enabling electrical compatibility with silicon integrated circuits. This work opens the possibility of monolithic integration of ALD ZTO‐based thin‐film electronics with silicon integrated circuits or onto large‐area flexible substrates.
out on the graphite anode surface under fast-charging conditions in high-energydensity cells. The irreversibility associated with Li plating leads to permanent loss of Li from the accessible reservoir and capacity fade, which is the key challenge that limits fast-charging of LIBs.Strategies to prevent and/or mitigate the impacts of Li plating on graphite have drawn great interest in recent years, including: 1) alternative anode materials such as lithium titanate, [6] titanium niobate, [7] and hybrid mixtures of hard carbon with graphite; [5] 2) modifying the electrode architecture to facilitate enhanced mass transport; [8][9][10][11][12] 3) asymmetric temperature modulation; [13] 4) surface coatings to modify interface behavior; [14][15][16][17] and 5) electrolyte modifications to increase
There is an increasing interest in additive nanomanufacturing processes, which enable customizable patterning of functional materials and devices on a wide range of substrates. However, there are relatively few techniques with the ability to directly 3D print patterns of functional materials with sub-micron resolution. In this study, we demonstrate the use of additive electrohydrodynamic jet (ejet) printing with an average line width of 312 nm, which acts as an inhibitor for area-selective atomic layer deposition (AS-ALD) of a range of metal oxides. We also demonstrate subtractive e-jet printing with solvent inks that dissolve polymer inhibitor layers in specific regions, which enables localized AS-ALD within those regions. The chemical selectivity and morphology of e-jet patterned polymers towards binary and ternary oxides of ZnO, Al 2 O 3 , and SnO 2 were quantified using X-ray photoelectron spectroscopy, atomic force microscopy, and Auger electron spectroscopy. This approach enables patterning of functional oxide semiconductors, insulators, and transparent conducting oxides with tunable composition, Åscale control of thickness, and sub-μm resolution in the x−y plane. Using a combination of additive and subtractive e-jet printing with AS-ALD, a thin-film transistor was fabricated using zinc−tin-oxide for the semiconductor channel and aluminum-doped zinc oxide as the source and drain electrical contacts. In the future, this technique can be used to print integrated electronics with sub-micron resolution on a variety of substrates.
Irradiation (6OCo y-rays) of crystalline bis(trans-but-2enoato)calcium induces a unique solid-state cyclodimerization reaction; the product, cis,trans-nepetic acid, is one of four possible diastereomers.Upon exposure to 6OCo y-rays, metal complexes and salts containing a$-unsaturated carboxylates exhibit extraordinary solid-state reactivity. Examples include the y-ray-induced stereospecific trimerization of sodium trans-but-2-enoate l a to give 21 and the regiospecific oxidation of trans-pent-2-enoate salts.2 Our search for new solid-state reactions involving metal alkenoates and alkynoates has included the refinement of techniques for 'engineering' and/or discovering short contacts between reactive unsaturated centres.3 In metal alkenoates the problem is more challenging than in alkynoates, where short contacts alone appear to be sufficient for solid-state reactivity.3.4 The required favourable orientations of the corresponding alkenoate planes does not occur, e.g. in bis(truns-but-2-enoato)lead,6 where the short distances between the double bonds are accompanied by nearly orthogonal (97.6") interplanar angles. Despite the great wealth of structural information available for metal carboxylates, the structures of simple metal carboxylates cannot be easily predicted at this time. Certainly, one expects that, for metals with a small radius or lower coordination number, the chances of finding short contacts (and by inference solid-state reactions) will be enhanced. Thus we chose to examine the structure and solid-state reactivity of bis(trans-but-2-enoato)calcium; we expected that, for calcium, the combination of small radius and relatively low coordination number would lead to a phase containing short contacts between the unsaturated centres.Anhydrous bis(trans-but-2-enoato)calcium l b was prepared from calcium carbonate and trans-but-2-enoic acid in water. In order to determine whether crystalline l b was reactive under 6OCo y-radiation, samples of l b were exposed to large y-*C02-M C02Na
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