Conductivity and touch-sensor application for atomic layer deposition ZnO and Al:ZnO on nylon nonwoven fiber mats

Abstract

Articles you may be interested inInfluence of dosing sequence and film thickness on structure and resistivity of Al-ZnO films grown by atomic layer deposition J. Vac. Sci. Technol. A 32, 041516 (2014); 10.1116/1.4885063 New approach toward transparent and conductive ZnO by atomic layer deposition: Hydrogen plasma doping J. Vac. Sci. Technol. A 31, 01A130 (2013); 10.1116/1.4768172 Atomic layer deposition of Al-doped ZnO thin films J. Vac. Sci. Technol. A 31, 01A109 (2013); 10.1116/1.4757764Effective atomic layer deposition procedure for Al-dopant distribution in ZnO thin films Flexible electronics and wearable technology represent a novel and growing market for next generation devices. In this work, the authors deposit conductive zinc oxide films by atomic layer deposition onto nylon-6 nonwoven fiber mats and spun-cast films, and quantify the impact that deposition temperature, coating thickness, and aluminum doping have on the conductivity of the coated substrates. The authors produce aluminum doped zinc oxide (AZO) coated fibers with conductivity of 230 S/cm, which is $6Â more conductive than ZnO coated fibers. Furthermore, the authors demonstrate AZO coated fibers maintain 62% of their conductivity after being bent around a 3 mm radius cylinder. As an example application, the authors fabricate an "all-fiber" pressure sensor using AZO coated nylon-6 electrodes. The sensor signal scales exponentially under small applied force (<50 g/cm 2 ), yielding a $10 6 Â current change under 200 g/cm 2 . This lightweight, flexible, and breathable touch/force sensor could function, for example, as an electronically active nonwoven for personal or engineered system analysis and diagnostics.

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

“…The ALD window for DEZ/water is measured to be ∼1.7−2.0 Å/cycle between 100 and 150°C, with decreasing growth rate at T > 150°C. 8,10,11 Therefore, similar growth is expected at 100 and 150°C, but reduced growth is expected for T = 175°C.…”

Flexible Thermoelectric ZnO–Organic Superlattices on Cotton Textile Substrates by ALD/MLD

“…A previous study on a ZnO thin film of 600 cycles deposited on a cotton-based material reported an effective conductivity of 24 S cm −1 which translates to 0.042 Ω cm in terms of resistivity. [21] Al-doped ZnO thin films deposited on nylon nonwoven fiber mats were previously reported to be approximately six times more conductive in comparison to pure ZnO, [22] while here the Al-doped ZnO thin film is over 20 times more conductive. As discussed above, the resistance and resistivity of the ZnO-organic superlattice thin films decrease as a function of the organic layer thickness.…”

“…[20] The ALD of ZnO and Al-doped ZnO on cotton and nylon nonwoven fiber mats has already been investigated in the context of fabricating conductive coatings for sensor applications. [21,22] While ZnO is known to be a promising TE material for remarkably high operating temperatures (about 1000 °C), [23] the relatively high thermal conductivity of bulk ZnO results in rather poor TE efficiency at low temperatures. However, the thermal conductivity of ZnO can be decreased by nanostructuring, which results in high scattering of the heat-carrying phonons while the electronic conductivity still remains at a reasonable level.…”

“…[18,21] Due to the porous nature of the cotton substrate, clearly longer precursor and subsequent N 2 purge pulse lengths need to be applied in comparison to typical flat and dense ALD substrates. [22] All ZnO-organic superlattice thin films were fabricated with ALD/MLD on cotton substrates with a predeposited Al 2 O 3 seed layer. The thickness of the inorganic ZnO block was kept constant in all superlattices, while three different thicknesses were tested for the organic interface.…”

Investigating the Nucleation of AlOx and HfOx ALD on Polyimide: Influence of Plasma Activation

“…ALD on polymeric substrates is widely used across many fields, such as surface modification of polymers [8][9][10], coatings [11][12][13], building 3D nanostructures (e.g., hollow fibers, hollow spheres, 3D meshes), filtration membranes [14], wearable electronics, displays, sensors, etc. [15][16][17][18][19][20][21]. However, one of the largest applications of ALD on polymers is the development of flexible glass diffusion [22][23][24][25][26][27][28], moisture [29][30][31][32][33] or copper [34,35] barriers for the microelectronics industry.…”