Initial stages of erbium disilicide formation on Si(001)

Morphological evolution of erbium disilicide nanowires on Si(001)

“…As found in previous studies, 6,20,24 Our results indicate that a structural transformation from the hexagonal to the tetragonal crystal structure takes place once the island height reaches the value of the c-axis of the tetragonal unit cell (1.326 nm compared with 0.409 nm of the hexagonal structure). The two phases of ErSi 2 -AlB 2 and ThSi 2 -are closely related, whereby the latter can be derived simply from the former by the introduction of two shear planes (for details, see Ref.…”

“…On the other hand, the growth of two different types of islands from the very beginning is not supported by our recent STM investigations of the initial stages of ErSi 2 formation on Si(001). 20 The two Er-induced superstructures c 4 ð 2 and 2 ð 3 observed on the substrate surface at submonolayer coverage can be regarded as precursors of the latter growth of ErSi 2 nanowires. In particular the observed 2 ð 3 phase exhibits already the basic structural elements of the (1100) plane-the growth plane of hexagonal ErSi 2 nanowires.…”

STM and DFT study of the Gd wetting layer reconstructions on the Si(001)-2×1 surface

“…To study of the formation of nanowires, it is essential to understanding the wetting layer formation and to determine how this layer influences the formation of nanowires, or indeed whether these layers might be precursors to the nanowires themselves. The appearance of a wetting layer has been reported for a number of RE metals, such as Gd [23], Dy [19,23], Er [20], Ho [15], Yb [21] and Nd [21]. These metals share common reconstructions as detailed in STM studies reported in the literature; however, the structure of the wetting layer has not been definitively determined for any of the silicides.…”

“…A major impetus for such studies is the search for new, cost effective methods to fabricate nanometer scale electronic devices. One system that has been investigated for this purpose is rare-earth (RE) silicides on the Si(1 1 1) [1][2][3] and Si(0 0 1) [4][5][6][7][8][9][10][11][12][13][14][15][16][17][18][19][20][21][22][23] surfaces. As first shown by Preinesberger et al [4], nanowires form in the initial growth stages of silicide overlayers for many RE metals, including: Dy [3][4][5][6][7][8][9][10], Er [5][6][7][11][12][13][14], Ho [6,9,15], Gd [1,2,7,16], Sc [7], Yb [17], Sm [5]...…”

Theoretical studies of Sm/Si(111)–n×1 (n=5, 7) and Sm/Si(111)–(8×2) structures

“…have attracted considerable attention as model candidates for heteroepitaxial growth on Si(1 1 1) due to their low lattice mismatch with Si(1 1 1) [1][2][3][4][5][6][7][8]. Rare-earth metal induced reconstructions on silicon are critically dependent on coverage and annealing temperature.…”