• PDF / 249,094 Bytes
• 6 Pages / 432 x 648 pts Page_size
• 63 Downloads / 282 Views

DOWNLOAD

REPORT

---

Atomic Layer Deposition of TiO2 ultrathin films on 3D substrates for energy applications Audrey Soum-Glaude1, Liang Tian2, Elisabeth Blanquet2, Virginie Brizé2, Laurent Cagnon3, Gaël Giusti4, Rached Salhi2, Stéphane Daniele5, Céline Ternon6 and Daniel Bellet4 1

Laboratory of PROcesses, Materials, Solar Energy (PROMES-CNRS), 7 rue du Four Solaire, 66120 Font-Romeu Odeillo, France 2 Laboratory of Science and Engineering of MAterials and Processes (SIMAP), 1130 rue de la Piscine, BP 75, 38402 Saint Martin d’Hères Cedex, France 3 Institute Néel, CNRS/UJF, 25 rue des Martyrs, BP 166, 38042 Grenoble cedex 9, France 4 Laboratory of Materials and Physical Engineering (LMGP), Grenoble INP Minatec, BP 257, 3 parvis Louis Néel, 38016 Grenoble, France 5 Institute of Research on Catalysis and Environment of Lyon (IRCELYON), 2 avenue Albert Einstein, 69626 Villeurbanne cedex, France 6 Laboratory of Technologies of Microelectronics (LTM), CEA-LETI/DTS, 17 rue des Martyrs, 38054 Grenoble Cedex 9, France

ABSTRACT In the present global environmental context, it becomes more and more critical to find efficient solutions to lower our energy consumption on one hand, and to produce energy from clean renewable sources on the other hand. Consequently, research efforts on materials for energy applications are intensifying. The present work aims at developing optoelectrical components usable for both energy saving (light emitting diodes) and renewable energy production (solar cells) by fabricating p-n heterojunctions based on a single semiconductor, titanium dioxide. TiO2 is indeed a very promising candidate: it is chemically and physically stable under irradiation, transparent to visible and near-infrared light (Eg = 3 - 3.5 eV), presents photocatalytic activity, is non-toxic and low cost, which permits to envisage its large scale use. In the present paper, the proposed architecture for both solar cells and LEDs is original as well as common for both applications: a three-dimensional architecture based on an anodic alumina nanoporous membrane which serves as nanomask for TiO2 growth in order to enlarge the effective surface of the components. TiO2 is synthesized by Atomic Layer Deposition (ALD), a technique particularly well adapted to the deposition of ultrathin films (from one monolayer to few tens of nanometers) on 3D porous substrates patterned with high aspect ratio nanopores. In this work, the capacity of synthesizing 3D nanostructures is demonstrated. TiO2 ultrathin films (10 to 100 nm) were grown by ALD on flat, micropatterned, microporous and nanoporous anodic alumina membranes (AAM) substrates. The films were highly conformal, as confirmed by SEM and TEM imaging. Both EDS and XPS analyses validated the dioxide film stoichiometry.

63

INTRODUCTION In the present global environmental context, it becomes more and more critical to find efficient solutions to lower our energy consumption on one hand, and produce energy from clean renewable sources on the other hand. Research efforts on materials for energy applications are thus int