Bi_1-xSb_x/Bi superlattice grown by molecular beam epitaxy

Superlattices of Bi_1-xSb_x/Bi have been grown by molecular beam epitaxy on CdTe(111) substrates. The typical multilayer, consisting of Bi_1-xSb_x (85 Å with x=0.16) and Bi (75-Å) layers repeated 50 times, was grown at a substrate temperature of 150°C. The samples were characterized by reflection high-energy electron diffraction (RHEED), θ-2θ x-ray diffraction analysis, and high-resolution transmission electron microscopy. The streaked RHEED patterns with clear Kikuchi lines and the x-ray satellite peaks indicate a good epitaxial layer quality. The bright field transmission electron microscopy image of the superlattice film confirms that a composition modulation exists, even though the Bi_1-xSb_x and Bi layers have only a slight image contrast.