ZnO deposition on metal substrates: Relating fabrication, morphology, and wettability

Abstract

It is not common practice to deposit thin films on metal substrates, especially copper, which is a common heat exchanger metal and practical engineering material known for its heat transfer properties. While single crystal substrates offer ideal surfaces with uniform structure for compatibility with oxide deposition, metallic surfaces needed for industrial applications exhibit non-idealities that complicate the fabrication of oxide nanostructure arrays. The following study explored different ZnO fabrication techniques to deposit a (super)hydrophobic thin film of ZnO on a metal substrate, specifically copper, in order to explore its feasibility as an enhanced condensing surface. ZnO was selected for its non-toxicity, ability to be made (super)hydrophobic with hierarchical roughness, and its photoinduced hydrophilicity characteristic, which could be utilized to pattern it to have both hydrophobic-hydrophilic regions. We investigated the variation of ZnO's morphology and wetting state, using SEMs and sessile drop contact angle measurements, as a function of different fabrication techniques: sputtering, pulsed laser deposition (PLD), electrodeposition and annealing Zn. We successfully fabricated (super)hydrophobic ZnO on a mirror finish, commercially available copper substrate using the scalable electrodeposition technique. PLD for ZnO deposition did not prove viable, as the ZnO samples on metal substrates were hydrophilic and the process does not lend itself to scalability. The annealed Zn sheets did not exhibit consistent wetting state results.

Influence of the Substrate, Process Conditions, and Postannealing Temperature on the Properties of ZnO Thin Films Grown by the Successive Ionic Layer Adsorption and Reaction Method

“…However, among the chemical route synthesis techniques, SILAR is one of the simplest and economically favorable chemical methods because it produces durable and adherent thin films comparatively at low processing temperatures and it does not require any sophisticated instruments. , Furthermore, this technique allows bulk region deposition on various kinds of insulating, semiconducting, and conducting metallic substrates, for example, soda lime glass (SLG) microscopy slides, fluorine-doped tin oxides, and Cu foil substrates, ,, just to name a few. The deposition technique relies on a wide range of processing parameters such as bath temperature, solution pH, complexing and dispersant agents, rinsing procedures, − and so forth to tailor physical properties of the deposit.…”

Annealing Effect on the Contact Angle, Surface Energy, Electric Property, and Nanomechanical Characteristics of Co40Fe40W20 Thin Films

“…On the other hand, the contact angles with glycerol were 76.7 • , 78.1 • , 79.6 • , 75.5 • , and 75.9 1 shows that the contact angle decreased with the increase of post-annealing temperature. It shows the same behavior as C 60 and ZnO [25][26][27][28].…”

“…Table 1 shows that the contact angle decreased with the increase of post-annealing temperature. It shows the same behavior as C60 and ZnO [25][26][27][28].…”

Effects of electric field during deposition on spray deposited indium‐doped zinc oxide films

“…Further increase of the voltage to 2.5 kV results in a flatter compact morphology of the deposited film [Figure (d)]. The modified morphology of zinc oxide can be useful for the hydrophobicity phenomenon , and the change in the surface wettability of IZO films deposited under different applied voltages is shown by the contact angle (Figure ).…”