Porous ZnO nanocrystalline films have drawn research attention due to improvement in gas sensing, adsorption, photocatalytic, and photovoltaic applications. However, scalable synthesis of porous nanostructures has been a challenge. Here, This paper reports a very easy, fast, and scalable one-step process for synthesis and deposition of porous ZnO nanocrystalline film by low-temperature atmospheric pressure plasma. The plasma is generated with radio frequency power using a metallic zinc wire as a precursor. Nanostructures have been synthesized and agglomerate to form a porous film at the substrate. Energy band structure of the deposited film has been investigated to understand the corresponding band alignment, which is relevant to many applications. An in-depth study of the grown nanostructured ZnO film has been included and characterized by X-ray diffraction, transmission electron microscopy, X-ray photoelectron spectroscopy, kelvin probe measurement, ultra-violet/visible absorption, and photoluminescence
