Formation of self-assembled Gd2O3 nanowire-like structures during epitaxial growth on Si(001). Issue 29 (13th May 2021) - Gribisch, Philipp
Abstract : The formation of nanowire-like structures during epitaxial growth of Gd2 O3 on Si(001) at high temperatures is investigated. The results are discussed by means of physical models. Abstract : The structural and morphological properties of gadolinium oxide (Gd2 O3 ) grown at high temperatures with molecular beam epitaxy on Si(001) were investigated for different stages of growth. The Gd2 O3 layers were grown at 850 °C with different oxygen partial pressures and substrate miscuts. RHEED and XRD investigations indicate an initial formation of silicide and a subsequent transformation into cubic Gd2 O3 with (110) orientation. The surface exhibits nanowire-like structures oriented orthogonally along with the [110] directions of the substrate, as indicated by AFM. Since on 4° off-cut Si(001) substrates the nanowire-like structures are mainly oriented in only one [110] direction, the orientation of the formed Gd2 O3 structures seems to be related to the dimer orientation of the (2 × 1) reconstructed Si(001) surface. The density and length of the nanowire-like structures can be tuned by a change in oxygen partial pressure. The results were discussed in terms of different physical effects, where a combination of desorption of silicon and the formation of a silicide layer in the initial stage of growth could be the reason for the growth behaviour, which is also supported through TEM investigations.