In Situ Conductance Analysis of Zinc Oxide Nucleation and Coalescence during Atomic Layer Deposition on Metal Oxides and Polymers

Abstract

Real time in situ conductance is collected continuously during atomic layer deposition (ALD) of zinc oxide films, and trends are used to study ALD nucleation on polypropylene, nylon-6, SiO2, TiO2, and Al2O3 substrates. The detailed conductance change during the ALD cycle is ascribed to changes in surface band bending upon precursor/reactant exposure. Conductive pathways form earlier on the inorganic surfaces than on the polymers, with Al2O3 substrates showing more rapid nucleation than SiO2 or TiO2, consistent with the expected density of nucleation sites (e.g., hydroxyl groups) on these different materials. The measured conductance is ohmic, and both two- and four-electrode configurations show the same data trends. Detailed analysis of conductivity at deposition temperatures between 100 and 175 °C shows faster conductivity decay at higher temperature during the water purge step, ascribed to thermally activated water desorption kinetics. Analysis of real-time conductivity during ALD of other material systems could provide further insight into key aspects of film nucleation and nuclei coalescence.

Dye adsorption on zinc oxide nanoparticulates atomic‐layer‐deposited on polytetrafluoroethylene membranes

“…The emerging peaks can be indexed to the (002) and (102) crystal plane of hexagonal wurtzite structure of ZnO (JCPDS, 36 2 1451). 27 For the sample with 30 ALD cycles, the ZnO diffraction peaks are not evident due to the insignificant amount of the deposited ZnO which confirms the previously discussed SEM results. As shown in Figure 4b, the intensity of diffraction peaks gradually enhanced with continuously increasing ALD cycle numbers, and the two peaks became remarkably strong with 100, 150, and 200 ALD cycles, thus confirming the increasing amount of ZnO deposited on PTFE membranes with rising ALD cycles.…”

Catalytic “MOF-Cloth” Formed via Directed Supramolecular Assembly of UiO-66-NH2 Crystals on Atomic Layer Deposition-Coated Textiles for Rapid Degradation of Chemical Warfare Agent Simulants

“…On polypropylene, some ALD precursors can readily diffuse into the polymer surface, leading to subsurface metal oxide nucleation and surface roughening. The extent of roughening depends on the polymer, nature of the precursor, ALD reactant dose times, and ALD process temperature. , …”

Atomic Layer Deposition for Polypropylene Film Engineering—A Review

“…[32] Using diethyl zinc (DEZ, (CH 3 CH 2 ) 2 Zn) and water as zinc and oxygen precursors, respectively, the deposition was carried out at 100 °C and 200 Pa. A 5 nm thick ALD Al 2 O 3 buffer layer was predeposited onto BOPP film to activate the chemically inert PP surface before ZnO deposition. [33] The ZnO deposition and subsequent growth (36 and 67 nm in thickness) assisted by such a buffer layer, were fulfilled on a 58 µm thick BOPP film with excellent uniformity. [34] Vaha-Nissi et al functionalized commercial PP dense films with ALD ZnO, aiming at the development of new package materials having an antibacterial barrier.…”

“…Figure 5a indicates the ZnO/Al 2 O 3 /PP composite PP films remaining conductive aging 16 months after deposition. [33,37] Also, Sweet et al subsequently proved their idea of patterning and selective coating of metal oxides on organic substrates by mean of ALD ZnO on PP and nylon-6 membrane. Similarly, using DEZ and water as atom precursors, the deposition was done under the pressure of 1.0 Torr and the temperature range of 120-160 °C.…”