Developing Spin Coated Nano‐Interfaces of Fluorescent Undoped and F‐Doped ZnO Quantum Dots

Thin nanostructured films of semiconductor materials are widely applied in various technological devices for next-generation technologies, such as microelectronics, photovoltaics, data storage, and optical and microwave nanodevices. The spin-coating technique is one of the easiest and most valuable strategies for creating thin films onto specific substrates to produce functional 2D nanodevices. However, optimizing the main operative parameters is fundamental in fabricating homogeneous films for optoelectronic, sensing, and other technological applications. Here, we propose a spin-coating protocol to develop nano-interfaces of fluorescent fluorine-doped ZnO quantum dots (QDs), highlighting how the deposition conditions and the choice of the substrate material result are decisive in defining the final structural organization of nanostructured interfaces. The combination of solid-state ellipsometry, x-ray reflectivity (XRR), and photoluminescence led to defining the best conditions to deposit fluorine-doped ZnO QDs onto silicon and glass substrates and to developing fluorescent nano-interfaces with controlled thickness and roughness. The best conditions to obtain a thin nanostructured film with good photoluminescence are guaranteed by a QDs suspension at a concentration equal to 3.0 mg mL−1 and a speed rotation of 3000 rpm using glass supports.