Deformation of small volumes of material using nanostructured strained layered superlattices

Abstract

A key aspect of nanostructured materials is that large coherency strains can readily exist between nano-sized phases. This can result in strengthening or in improved ductility. However, in conventional materials, it can be very difficult to separate the effects of coherency strain from other phenomena. Electronic grade single crystal semiconductor structures provide a means to study the effects of coherency strain in isolation. In this work, thin coherently strained InGaAs superlattices grown on thick InP substrates were tested in three-point bending at 500°C. The stress–strain curves of the specimens were measured, and from them, analysis yields the actual stress supported by the thin superlattice. The superlattices display extraordinary strength compared to the corresponding bulk material. This effect can be attributed only to the coherency strain in the superlattices.