Study of the effect of thin ALD oxide coatings on the stability of silver nanowire based
transparent electrodes
S. AghazadehChors
1,2
, V. Nguyen
1
, M. Lagrange
1
, A. Khan
1,3
, T. Sannicolo
1,4
, N.D. Nguyen
2
,
D. Muñoz-Rojas
1
, D. Bellet
1,*
1
Univ. Grenoble Alpes, LMGP, F-38000 Grenoble, France
CNRS, LMGP, F-38000 Grenoble, France.
2
Laboratoire de Physique des Solides, Interfaces et Nanostructures; Département de
Physique, Université de Liège.
Allée du 6 Août 17, B-4000 Liège, Belgique.
3
Department of Physics, Univ. of Peshawar, Pakistan
4
Univ. Grenoble Alpes, F-38000 Grenoble, France
CEA, LITEN, F-38054 Grenoble, France
Current research on new Transparent Conductive Materials focuses on emerging materials
such as carbon-based materials, graphene or metallic nanowire networks. The latter concern
mainly silver nanowires (AgNW). Although AgNW networks seem to approach ITO values in
terms of optical transparency and electrical sheet resistance, (90% and 10 Ω/sq respectively)
[1], overcoming a rather poor thermal and electrical stability still remains a challenge. While
most device fabrication processes require thermal annealing steps to optimize their electrical
properties, heating can modify AgNW network morphology. Moreover, when used as
transparent heaters, an electrical current induces specimen heating (due to Joule effect) and
then imposing AgNW network to be resistant to heat.
One way to improve thermal stability of AgNW networks is to use a thin layer of a
passivating metal oxide (such as ZnO or TiO
2
) which induces stability improvements [2]. So
far, our group has studied the effect of a thin layer of TiO
2
deposited by ALD on the thermal
and electrical stability of AgNWs networks. Our studies show that even a TiO
2
layer as thin
as 5 nm
can lead to an extension of thermal stability from 270 °C to 420 °C. The oxide
coating also increases the value of the electrical failure voltage. This stability enhancement
comes with nearly no change in optical transparency (less than 1%). Currently we are
replacing the ALD deposition method with a new approach called Spatial ALD (SALD). This
technique does not require vacuum, it is much faster than conventional ALD and is easily
scalable [3]. Here we will present a comprehensive study of the effect of deposition
parameters, passivation film thickness on the electrical and optical properties of AgNWs
based transparent electrodes. Optimized parameters will allow the integration in devices such
as transparent heaters. We will demonstrate that adding a passivation layer increases the
breakdown voltage, making the devices stable at higher voltage or temperature.
References:
[1] Lagrange, M., Langley, D. P., Giusti, G., Jiménez, C., Bréchet, Y., & Bellet, D. (2015).
Optimization of silver nanowire-based transparent electrodes: effects of density, size and thermal
annealing.
Nanoscale
,
7
(41), 17410-17423.
[2] Kim, A., Won, Y., Woo, K., Kim, C. H., & Moon, J. (2013). Highly transparent low resistance
ZnO/Ag nanowire/ZnO composite electrode for thin film solar cells.
ACS nano
,
7
(2), 1081-1091.
[3] Muñoz-Rojas, D., & MacManus-Driscoll, J. (2014). Spatial atmospheric atomic layer deposition: a
new laboratory and industrial tool for low-cost photovoltaics.
Materials Horizons
,
1
(3), 314-320.
PS1 34
-190-
