Organic Crystal Template‐Directed Fabrication of 3D Nanostructured Alumina Thin Films via Atomic Layer Deposition

Abstract This article presents a new approach for fabricating 3D nanostructured alumina thin films by combining organic crystal templating with the atomic layer deposition (ALD) process. Hierarchical mesocrystals of glutathione and the chiral amino acid L‐histidine serve as well‐defined templates, directing the morphology of conformal Al 2 O 3 thin films grown under low‐temperature ALD conditions. Upon removal of the organic templates, the resulting free‐standing metal oxide films retain the complex geometry of the original organic structures. Comprehensive characterization, including X‐ray diffraction (XRD), X‐ray photoelectron spectroscopy (XPS), and electron microscopy, confirms the structural integrity and chemical composition of the sequential fabrication steps. This template‐assisted strategy bridges organic crystal engineering with inorganic thin films synthesis, offering a platform for designing of advanced materials with tailored porosity, surface area, and functionality. The method opens new possibilities for applications in heterogeneous catalysis, optical sensing, and nanophotonic devices.