Double-layer effect on electrothermal properties of transparent heaters

Abstract

Phone: þ82 10 8717 0978, Fax: þ82 2 958 5229 Transparent double-layer heaters that consist of aluminumdoped zinc oxide and fluorine-doped tin oxide films are prepared by electron cyclotron resonance-metal organic chemical vapor deposition and RF-sputtering systems, in sequence. The double-layered transparent conducting oxide film is designed and prepared to achieve both of high conductivity and high-temperature performance. This double-layer structure has lower sheet resistance, due to the grain size increase with respect to the single-layer films. The fluorine-doped tin oxide/aluminum-doped zinc oxide double-layer film shows a sheet resistance as low as 36.7 V sq À1 , and an optical transmittance of $82%, which are suitable properties for low-voltage transparent heaters. Hall measurement results show that the double-layer film has remarkably increased conductivity and decreased resistivity. In addition, the time-versus-temperature profile shows that the performance of the fluorine-doped tin oxide/aluminumdoped zinc oxide double layer is superior to that of the aluminum-doped zinc oxide and fluorine-doped tin oxide single-layer films.

Transparent Heaters: A Review

“…Kim et al explored the use of bilayers by combining AZO and FTO deposited by sputtering and chemical vapor deposition (CVD), respectively. [ 84 ] They observed that both conductivity and transparency improved for bilayers with respect to single layers of the same thickness, as demonstrated in Figure 5e. [ 84 ] This is attributed to the higher overall particle size in the film, which affects both mobility and transparency.…”

“…As a first approximation, this value does not depend much on the material that composes the TH. Accordingly, this range of τ values was observed for THs composed of AgNW networks, [ 45 ] CNT networks, [ 27 ] TCO, [ 84 ] conductive polymers, [ 50 ] electrospun nanofibers, [ 76,85 ] or graphene. [ 86 ] For efficient THs, the τ value mainly depends on the characteristics of the substrate: the thinner the substrate, the shorter the characteristic time.…”

“…[ 84 ] They observed that both conductivity and transparency improved for bilayers with respect to single layers of the same thickness, as demonstrated in Figure 5e. [ 84 ] This is attributed to the higher overall particle size in the film, which affects both mobility and transparency. The best results, reported in Figure 5e, were obtained for FTO/AZO bilayers for which temperatures above 70 °C were obtained for a bias voltage of 12 V. [ 84 ] Roul et al studied rigid and flexible AZO‐based TCOs by depositing AZO on glass and polyethylene terephthalate (PET) substrates by magnetron sputtering.…”

“…Reproduced with permission. [ 84 ] Copyright 2014, Wiley‐VCH. f) Measured temperature versus time for a 100 nm thick AZO‐based TH, deposited on mica substrates of different thicknesses, illustrating the role played by the thermal inertia of the substrate in terms of response time.…”

“…Despite TCOs being the oldest studied TCMs, there are surprisingly few reports in the literature dealing with the application of TCOs as THs. The studies reported so far involve ZnO‐based materials, Ga‐doped ZnO (GZO), [ 126–128 ] and AZO, [ 60,84,127,129 ] FTO, [ 84 ] and ITO. [ 130–133 ] Indeed, TCOs have been mainly investigated in the framework of industrial research and development, which is generally not associated with scientific publications.…”