Modulated contrast and associated diffracted intensity of GaPySb1-y layers grown using organometallic vapor phase epitaxy

We have investigated the modulated structures and its associated diffracted diff_x000B_use intensity, of organometallic vapor phase epitaxially grown GaPSb (001) layers by using transmission electron microscopy (TEM) and transmission electron diff_x000B_raction (TED). The TEM results reveal the co-existence of a _x000C_fine-scale modulated contrast and a _x000C_fine-scale speckled contrast. In addition, a _x000C_fine needle-like contrast is observed. The [001] TED results show lines of [110]-oriented diff_x000B_use intensity diffuse streaks passing through the fundamental reflections, satellite spots at 1/4g[220] positions, and a [010]-oriented diff_x000B_use intensity with spacing of 1/6g[040]. Simulations using the Valence Force Field model were performed to understand the origin of the di_x000B_ffracted features. The observed distributions of di_x000B_ffuse intensity are shown to be partially consistent with random disorder. Furthermore, the [110]-oriented diff_x000B_use lines are attributed to a static displacement of the sites of the mixed sublattices.