Realization of Large-Domain Barium Disilicide Epitaxial Thin Film by Introduction of Miscut to Si(111) Substrate

Abstract

The domain structure of BaSi2 epitaxial films grown on vicinal Si(111) substrates has been studied in order to fabricate high-quality BaSi2 crystals with large domains. The X-ray pole figure measurement shows that the BaSi2 films grown on vicinal substrates as well as the on-axis substrate consist of three epitaxial variants which are equivalent in terms of 60° in-plane rotations, and that one of the variants is dominant in the film grown on the 2°-inclined substrate. The orientation maps produced by electron backscatter diffraction show that the domains with the b axis parallel to the miscut direction are larger than the others in the film grown on the 2°-inclined substrate, while the domain sizes of three variants are found similar in the films grown on the on-axis and 4°-inclined substrates. The possible origin of the large domain formation is discussed with the focus on the initial growth stage observed by atomic force microscopy. Nucleation from the step edge is proposed as the mechanism of the large-domain formation considering the lattice matching to the step edge, while nucleation is suggested to occur at the terrace edges on the 4°-inclined substrate.

Exploring the potential of semiconducting BaSi2for thin-film solar cell applications

“…4, panels (c) and (c') as well as (d) and (d'). The grain size of BaSi2 variants can be increased by using a vicinal Si substrate [31,32] or by employing large grained RDE-grown BaSi2 templates [33]. The grain size can reach approximately 9 μm and 4 μm for BaSi2 on Si(001) and Si(111), respectively.…”

Epitaxial growth of BaSi2 films with large grains using vicinal Si(111) substrates

“…In Fig. 4, red regions covered almost half the surface, meaning that BaSi 2 starts to grow at the edge of terraces [9]. terrace width in Fig.…”

“…Recently we have achieved a grain size of over 4.0 μm for BaSi 2 epitaxial films by optimizing the growth condition for template layers even on exact Si(111) [8]. In addition, it turned out that one of the three epitaxial variants was dominantly grown when we used vicinal Si(111) substrates [9]. However, the grain sizes in such BaSi 2 films are limited to about 0.2 μm, the same as conventional BaSi 2 films [9,10].…”

“…In addition, it turned out that one of the three epitaxial variants was dominantly grown when we used vicinal Si(111) substrates [9]. However, the grain sizes in such BaSi 2 films are limited to about 0.2 μm, the same as conventional BaSi 2 films [9,10]. It is therefore reasonable to assume that we will be able to achieve larger grains than ever by combining vicinal Si(111) substrates and optimized growth conditions for template layers.…”

Formation of large-grain-sized BaSi2 epitaxial layers grown on Si(111) by molecular beam epitaxy

“…Thus, the formation of large grains is important for solar cell applications. We have previously succeeded in the expansion of BaSi 2 grains in films using vicinal Si(001) and Si(111) substrates [13,14]. In this paper, we aimed to form large-grain-sized BaSi 2 exceeding 1 µm on exact Si(111) substrates by adjusting the growth conditions and post-annealing.…”