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.

Advancements in 3D printing have initiated a paradigm in device fabrication. Electrohydrodynamic jet (e-jet) printing is a high-resolution 3D printing method that enables customizable patterning of thin-film structures, while reducing fabrication complexity and achieving high-resolution patterns with a wide variety of materials. However, to date, e-jet printing has focused on additive material deposition, rather than patterning through material subtraction. This work proposes displacement-based e-jet printing using solvent inks for subtractive patterning of polymer thin films, with microscale resolution in the x–y plane and nanoscale control in the z (dissolving) direction. The behavior of displacement-based e-jet printing is characterized using atomic force microscopy, and two methodologies are developed for controlling the linewidth and displaced depth. An example of area-selective thin film deposition on displacement-based e-jet patterns is provided to demonstrate the applicability of this patterning technique for printable microscale devices.

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We demonstrate tunable structural color patterns that span the visible spectrum using atomic layer deposition (ALD). Asymmetric metal–dielectric–metal structures were sequentially deposited with nickel, zinc oxide, and a thin copper layer to form an optical cavity. The color response was precisely adjusted by tuning the zinc oxide (ZnO) thickness using ALD, which was consistent with model predictions. Owing to the conformal nature of ALD, this allows for uniform and tunable coloration of non-planar three-dimensional (3D) objects, as exemplified by adding color to 3D-printed parts produced by metal additive manufacturing. Proper choice of inorganic layered structures and materials allows the structural color to be stable at elevated temperatures, in contrast to traditional paints. To print multiple colors on a single sample, polymer inhibitors were patterned in a desired geometry using electrohydrodynamic jet (e-jet) printing, followed by area-selective ALD in the unpassivated regions. The ability to achieve 3D color printing, both at the micro- and macroscales, provides a new pathway to tune the optical and aesthetic properties during additive manufacturing.

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