Thermoelectric La-doped SrTiO 3 epitaxial layers with single-crystal quality: from nano to micrometers

Mihai Apreutesei (1) , Régis Debord (2) , Mohamed Bouras (3) , Philippe Regreny (3) , Claude Botella (3) , Aziz Benamrouche (4) , Adrián Carretero-Genevrier (5, 6) , Jaume Gazquez (7) , Geneviève Grenet (3) , Stéphane Pailhes (2) , Guillaume Saint-Girons (3) , Romain Bachelet (3)

1 MATEIS - Matériaux, ingénierie et science [Villeurbanne]
2 ILM - Institut Lumière Matière [Villeurbanne]
3 INL - H&N - INL - Hétéroepitaxie et Nanostructures
4 INL - Nanolyon - INL - Plateforme Technologique Nanolyon
5 IES - Institut d’Electronique et des Systèmes
6 M2A - Matériaux, MicroCapteurs et Acoustique
7 ICMAB - Institut de Ciència de Materials de Barcelona

High-quality thermoelectric La 0.2 Sr 0.8 TiO 3 (LSTO) films, with thicknesses ranging from 20 nm to 0.7 μm, have been epitaxially grown on SrTiO 3 (001) substrates by enhanced solid-source oxide molecular-beam epitaxy. All films are atomically flat (with rms roughness < 0.2 nm), with low mosaicity (<0.1°), and present very low electrical resistivity (<5 × 10 −4 Ω cm at room temperature), one order of magnitude lower than standard commercial Nb-doped SrTiO 3 singlecrystalline substrate. The conservation of transport properties within this thickness range has been confirmed by thermoelectric measurements where Seebeck coefficients of approximately-60 μV/K have been recorded for all films. These LSTO films can be integrated on Si for nonvolatile memory structures or opto-microelectronic devices, functioning as transparent conductors or thermoelectric elements.

Domaines: Electronique

Mihai Apreutesei, Régis Debord, Mohamed Bouras, Philippe Regreny, Claude Botella, et al.. Thermoelectric La-doped SrTiO 3 epitaxial layers with single-crystal quality: from nano to micrometers. Science and Technology of Advanced Materials, 2017, 18 (1), pp.430 - 435. ⟨10.1080/14686996.2017.1336055⟩. ⟨hal-01628269⟩