Growth and structural characterization of a Pb_(1-x)Ca_xS_(1-y)Se_y/PbS heterostructure prepared by hot-wall epitaxy

摘要

We have investigated the preparation of a Pb_(1-x)Ca_xS_(1-y)Se_y/PbS heterostructure on a BaF_2(111) substrate, by hot-wall epitaxy. It was confirmed by high-resolution X-ray diffraction with a four-crystal monochromator, that the Pb_(1-x)Ca_xS_(1-y)Se_y system was successfully lattice-matched to PbS in the heterostructure. In the lattice mismatch samples, a rhombohedral distortion was formed in the heterostructure, according to a reciprocal space map obtained at symmetric (222) and asymmetric (264) Bragg reflections. The crystallinity of the upper PbS layer was limited by mosaicity, in the case of samples with a large misfit between the PbS layer and the Pb_(1-x)Ca_xS_(1-y)Se_y under-layer. The typical strain induced in the PbS layer was 3.0 x 10~(-4) in the perpendicular direction and - 1.6 x 10~(-4) in the parallel direction, when the plane width of the Pb_(1-x)Ca_xS_(1-y)Se_y layer was 0.79275A, at the asymmetric (264) reflection.