Morphology and composition of Au catalysts on Ge(111) obtained by thermal dewetting

S Hajjar (1) , G Garreau (1) , L Josien (1) , Jean-Luc Bubendorff (2) , D Berling (1) , A Mehdaoui (3) , C Pirri (1) , T Maroutian (4) , C Renard (5) , D Bouchier (4) , Matthieu Petit (6) , A Spiesser (6) , Tuan Minh Dau (6) , L Michez (6) , V Le Thanh (6) , T.O. Mentes (7) , M. A. Nino (7) , A Locatelli (7)

1 IS2M - Institut de Science des Matériaux de Mulhouse
2 LPSE - Laboratoire de physique et de spectroscopie électronique
3 GEMAC - Groupe d'Etude de la Matière Condensée
4 IEF - Institut d'électronique fondamentale
5 LLR - Laboratoire Leprince-Ringuet
6 CINaM - Centre Interdisciplinaire de Nanoscience de Marseille
7 Elettra Sincrotrone Trieste

We investigate the chemical and morphological structure of the Au nanodots on Ge(111) which serve as catalysts for the formation of epitaxial Ge nanowires. The spatial localization of Au is investigated by X-ray spectromicroscopy and transmission electron microscopy. We show that dewetting of an Au film on Ge(111) gives rise to a thin Au-Ge wetting layer and Au-Ge dots. These dots are crystallized but not with a single crystallographic orientation. Thanks to the spatially resolved X-ray and transmission electron microscopy measurements, a chemical characterization of both binary Au-Ge catalysts and wetting layer is obtained at the nanoscale. We show that Ge vertical growth is achieved even without external Ge supply.

Domaines: Science des matériaux [cond-mat.mtrl-sci]

S Hajjar, G Garreau, L Josien, Jean-Luc Bubendorff, D Berling, et al.. Morphology and composition of Au catalysts on Ge(111) obtained by thermal dewetting. Physical Review B: Condensed Matter and Materials Physics (1998-2015), 2011, 84 (12), pp.125325. ⟨10.1103/PhysRevB.84.125325⟩. ⟨hal-01122603⟩