Speaker
Description
Transparent conducting oxides (TCOs) are materials with low optical absorption in the visible [1], which makes them particularly suitable for key applications in information technologies (displays…) and energy harvesting (photovoltaics...). Among them, Indium Tin Oxide (ITO) still plays, in spite of In scarcity, a crucial role, especially in niche applications where the chemical stability in water solutions is a decisive factor (electrochemical sensors).
In this work we report on the production of highly anisotropic resistivity surfaces by fs-laser irradiation of ITO films at high repetition rate at 1030 nm [2]. Electrical anisotropy appears as a consequence of the formation of Laser Induced Periodic Structures (LIPSS) at the material surface. These self-organized structures [3] have been coherently extended over cm-sized regions. We have identified two main optimized processing conditions. At high fluence, nearly complete ablation at the valleys of the LIPSS and strong ablation at their ridges, accompanied by a preferential In-loss, lead to an insulating structure in the direction transverse to the LIPSS and conductive in the longitudinal one. At a lower fluence, the material at the LIPSS ridges remains essentially unmodified while partial ablation is observed at the valleys. The latter structures show a longitudinal conductivity twice the transverse one, and a resistivity similar to that of the pristine ITO film. The compositional changes induced as laser pulses accumulate, condition the LIPSS evolution and thus the result of the structuring process.
[1] K. Ellmer, Nat. Photonics 2012, 6, 809
[2] C. Lopez‐Santos, D. Puerto, J. Siegel, M. Macias‐Montero, C. Florian, J. Gil‐Rostra, V. López‐Flores, A. Borras, A. R. González‐Elipe, J. Solis, Adv. Opt. Mater. 9, 2001086 (2020).
[3] J. Bonse, S. Hohm, S. V. Kirner, A. Rosenfeld, J. Kruger, IEEE J. Sel. Top. Quantum Electron. 2017, 23, 9000615
| Speaker Country | Spain |
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