Competitive Relaxation Mechanisms in Strained Epitaxial InGaSb on GaSb Substrate

Abstract

Abstract Hetoroepitaxial growth of III-V compounds can produce both novel structures for fundamental research and electronic/photonic devices for practical applications. Antimony-based compounds are interested since they can interact with light in longer wavelengths ranging from near-infrared to terahertz frequency domains. In this work, we present an experimental observation of step-decorated surface and dislocation lines formed in an epitaxial In0.17Ga0.83Sb layer. The growth is performed by solid-source molecular beam epitaxy on (001) GaSb substrate at 400°C with the InGaSb deposition rate of 0.12 monolayer per second. The atomic force microscopy shows that the regular atomic steps are generally misaligned with the surface dislocation lines. The average distance between the steps is about 200 nm and the presence of dislocation lines affects the subsequent growth. Zigzag step-edge structure observed near the intersection of the step-edges and the dislocation lines can be explained by simple strain-considered models. Enhanced and depleted growth areas can be related to the degree of underneath strain. The understanding of this phenomena might lead to the simple and practical realization of regular arrays of nanostructures such as quantum wires and quantum dots.