Epitaxy relationships between Ge-islands and SiC(0 0 0 1) K. Aı ¨t-Mansour a, * , D. Dentel a , L. Kubler a , M. Diani b , J.L. Bischoff a , D. Bolmont a a Faculte ´ des Sciences, LPSE, UMR CNRS 7014, 4, rue des Fre `res Lumie `re, 68093 Mulhouse, Cedex, France b De ´partement de Physique, Faculte ´ des Sciences et Techniques, LSGM, BP 416, Tanger, Maroc Accepted 18 July 2004 Available online 18 October 2004 Abstract Reflection high-energy electron diffraction (RHEED) has been used to determine epitaxy relationships and in-plane orientations between Ge and SiC(0 0 0 1). Three monolayers of Ge have been deposited at 500 8C on a graphitized SiC (6H3  6H3)R308 reconstructed surface, this surface supporting epitaxial Ge island growth in a Volmer–Weber mode. Nucleation of relaxed Ge-islands gives rise to transmission electron diffraction patterns allowing to deduce that pure Ge grows according to only one epitaxy relationship Ge{1 1 1}//SiC(0 0 0 1). These {1 1 1}-Ge-islands have two in-plane orientations, a preferential one, Geh-1-12i//SiCh1-100i and a minority one, Geh-1-12i//SiCh10-10i, deduced one from the other by a 308 rotation around the h111i-Ge (or [0 0 0 1]-SiC) growth axis. Due to the three-fold symmetry of the {1 1 1}-Ge plane, each in-plane orientation is degenerated into two twin orientations, differing by a 1808 angle around Geh111i. # 2004 Elsevier B.V. All rights reserved. PACS: 61.14.Hg; 68.37.Ps; 68.55.-a; 79.60.-i; 81.15.Hi. Keywords: Reflection high-energy electron diffraction (RHEED); Epitaxy relationships; In-plane orientations; Germanium (Ge) islands; Silicon carbide (SiC); C-rich reconstructed surface 1. Introduction In order to design new electronic devices, the elaboration of low-dimensional structures with IV-IV compound and alloy semiconductors has been the subject of many studies in surface physics and materials science. The experience gained in Ge nanostructure growth on standard or modified Si substrates – a prototypical quantum system – has motivated similar works on silicon carbide (SiC) ones. Thus, Ge growth on on- and off-axis SiC surfaces has been investigated [1–7] with an increasing interest justified by the desire to develop optoelectronics in SiC technology. Very recently, it has been demonstrated that Ge nanocrystals embedded in a wide-band gap (3 eV) SiC matrix – by ion implantation with subsequent annealing – allow strong carrier confinement. Electro- www.elsevier.com/locate/apsusc Applied Surface Science 241 (2005) 403–411 * Corresponding author. Tel.: +33 3 8933 6007; fax: +33 3 8933 6083. E-mail address: k.ait-mansour@uha.fr (K. Aı ¨t-Mansour). 0169-4332/$ – see front matter # 2004 Elsevier B.V. All rights reserved. doi:10.1016/j.apsusc.2004.07.054