Heteroepitaxial growth of highly anisotropic $S{b}_{2}S{e}_3$ films on GaAs

Abstract

The epitaxial integration of anisotropic materials with mainstream cubic semiconductors opens new routes to advanced electronic and photonic devices with directional properties. In this work, we synthesize heteroepitaxial thin films of orthorhombic "quasi-1D" $S{b}_{2}S{e}_3$ on cubic GaAs(001) using molecular beam epitaxy. Traditionally, the synthesis of anisotropic films with low symmetry materials is challenging due to multiple grain orientations that form. On a macroscopic scale, such a film tends towards isotropic properties, even if individual grains possess anisotropic responses. We achieve epitaxial $S{b}_{2}S{e}_3$ grains on pristine homoepitaxial GaAs templates at low temperatures of 180-200 °C. With the $S{b}_{2}S{e}_3$ 1D axis aligned in-plane to GaAs [110] and the primary van der Waals direction lying out-of-plane, we find a birefringence of 0.2 between in-plane orthogonal directions and a giant out-of-plane birefringence greater than 1 at telecom wavelengths. Growth at higher temperatures up to 265 °C yields $S{b}_{2}S{e}_3$ of an unusual in-plane rotated texture that further enhances the in-plane optical index anisotropy to 0.3.

18 pages, 4 figures

References in corpus (5)

• Giant optical anisotropy in transition metal dichalcogenides for next-generation photonics
• Identifying the ground state structures of point defects in solids
• Lone pair driven anisotropy in antimony chalcogenide semiconductors
• Optimization of the growth of the van der Waals materials Bi2Se3 and (Bi0.5In0.5)2Se3 by molecular beam epitaxy
• Time-resolved reversible optical switching of the ultralow-loss phase change material Sb2Se3